Every tool, filterable

Pick the two things you are joining and the conditions it has to survive, and this works out which adhesive will actually hold — with open time, clamp time, full cure and the surface prep that make...

A board foot is 1" × 12" × 12". Enter the dimensions of your boards and the quantity, and get the board footage, linear footage and cost.

Calculate how many bricks you need for any wall — including mortar joints, waste, and pallets to order. Works for UK standard, metric, and imperial bricks.

Keeps the dates that are easy to miss and expensive to miss in one place: MOT, tax, insurance, service intervals, and the four items that actually cause MOT failures. Saved in your browser only — n...

Slimy and smelly means too much nitrogen; dry and stubborn means too much carbon. Tell it what’s gone into the heap and it estimates your C:N ratio and exactly what to add next.

Calculate cement, sand, gravel, and water for any concrete project — from fence posts to shed bases.

Work out the width needed per curtain panel and the finished drop, with optional hem and heading allowances for homemade curtains.

Answer a few questions about the damp patches, mould and smells in your home and get the most likely cause — condensation, penetrating damp, rising damp or a leak — with the practical fixes and whe...

Check how far a joist can safely span: pick the lumber size, spacing, wood type and load, and get the maximum span plus the beam and post spacing to match.

Calculate boards, joists, posts, screws, and total cost for a timber decking project. Works for softwood, hardwood, and composite decking.

A common rule is spacing ≈ 0.5–0.75 × ceiling height, with the first lamp about half that from the wall. Check beam angle and joists — this is a layout sketch, not a lighting design.

Order the right amount of board: enter the wall and ceiling area, pick a sheet size and wastage, and get the sheet count plus the joint compound, tape and screws to finish it.

Calculate posts, panels, gravel boards, concrete, and total cost for a garden fence. Works for panel fencing, closeboard, and picket styles.

Calculate how much gravel, slate, chippings, or aggregate you need for driveways, paths, patios, or garden beds. Includes tonnes, bulk bags, and cost.

The tiles are one thing — the grout and adhesive to fix them are another. Enter the tiled area, tile size and joint width to work out how much grout and thinset to mix.

Create a clear room-by-room record of belongings, quantities, serial numbers and replacement values for a move or an insurance review. Add, search, export, and re-import a JSON backup. Entries stay...

Keep routine home jobs, appliance servicing and the last-completed dates together. Sort upcoming work, log a completion, and export a backup or spreadsheet-friendly service log. It saves in this br...

Compare up to three contractor estimates on a more like-for-like basis. Record each quote’s total, known extras, included work, exclusions, schedule, payment terms and guarantee notes—without prete...

Estimate how much you could save by insulating your loft, walls, or floor. Based on UK energy prices.

Work out how many packs of laminate to buy: enter the room, the plank size, planks per pack and pack price, and this adds the wastage so you don't run short mid-lay.

UK, US and EU bed names are not the same size. A UK king is 150 × 200 cm; a US king is 193 × 203 cm. Fitted sheets do not stretch that gap. Depth (deep-fitted) is separate.

Turn a balcony, windowsill or tiny yard into real food. Tell it your space, sun and season and it ranks what to grow by calories per square metre — with a sowing calendar, harvest forecast and mone...

Set the saw for a perfect corner: enter the corner angle and pick flat or crown molding, and get the miter and bevel angles to dial in.

Everyone under-buys boxes by half. Tell it the size of the place, the people in it and how long you’ve been there — get a realistic shopping list plus the packing timeline removal crews wish everyo...

Volume = area × depth. A 50 litre bag is 0.05 m³. Bark mulch is usually 5–8 cm; paths can be 10 cm. Order a little extra for settling — bags are sold by loose volume.

That low hum at night, a whine from the walls, a buzz nobody else hears. Record it with your microphone and this finds the dominant pitches and matches them to likely sources: mains electricity (50...

Calculate exactly how much paint you need for any room. No more buying 5 tins for a cupboard.

Calculate the perfect height and hook position so your pictures hang straight and look professional.

Look up the right pipe diameter for any domestic plumbing job. Covers hot/cold water, central heating, and waste.

How many plants fit a bed at a given spacing. Square grid is simplest; triangular (hex) packing fits about 15% more. Leave paths out of the length and width.

Calculate how much plaster, render, or screed you need for walls, ceilings, or floors. Includes bags, coverage, and estimated cost.

Litres and gallons from length, width and average depth. Rectangular, circular and oval. Chemical dosing is per 1,000 litres — this is volume only, not a treatment plan.

Throw ratio = distance to screen ÷ image width. A 1.5:1 lens 3 m from the wall makes a 2 m wide picture. 16:9 assumed unless you change it. Check the projector’s own min/max zoom range.

1 mm of rain on 1 m² is 1 litre. Multiply by a runoff coefficient (tiles ~0.85, felt ~0.8). UK roofs often yield more than a water-butt can hold — size the tank, not just the dream.

Make a room-by-room check-in record while details are fresh. Note meter readings, keys, visible wear or damage, things not tested, and photo references. Entries stay in this page until you copy or ...

Plan a repair event around the skills and hours people actually offer. Match repair requests to volunteers, show the waiting list, and calculate the proposed workload without promising a repair wil...

The throwaway economy wants you to bin it and buy another. This decider weighs the three things that actually matter — cost per useful year, embodied carbon and remaining life — and tells you hones...

Roof pitch is the rise in inches for every 12" of run. Enter the pitch and half-span (run), and get the rafter length, angle and roof-area multiplier.

Estimate the heating and cooling load for a room: area, ceiling height, insulation, sun exposure, occupancy and climate all move the number of BTUs you need.

Drag and drop furniture to plan your room layout. Scale-accurate 2D top-down view.

Convert plan measurements to real dimensions or real dimensions to a drawing, with explicit units and a photocopy enlargement or reduction factor.

Look up the right drill bit for any screw size, wall plug colour, and pilot hole diameter. No more guessing.

Calculate the right bracket size, spacing, and load capacity for your shelf project.

Rough cubic yards from room waste, rubble or bags. UK skips are sold in yards: 4, 6, 8, 12, 16. Loose waste settles; rubble is heavy — many yards cap weight before the skip looks full. Not a quote.

Size a straight staircase: enter the total rise and your preferred riser height, and get the number of steps, the tread depth, total run and the stair angle — checked against the comfortable 2×rise...

Frame a wall the way a carpenter would: enter the wall length, stud spacing, openings and corners, and get the stud count, plate lumber and headers to order.

Give spare materials another useful life: match community projects to offered quantities, keep units consistent, and show leftovers and unmet needs before arranging collection.

Calculate tiles, planks, or carpet needed for any room — including waste and cuts.

Recommend a sofa distance from screen diagonal and resolution. Uses SMPTE 30° field-of-view, THX 40°, and a sharpness seat where 4K/1080p pixels sit at about 1 arc-minute. Advice, not a living-room...

Not sure what fixings to use? Tell us your wall type and what you're hanging — we'll tell you exactly what to buy.

Calculate how many rolls of wallpaper you need — accounting for pattern repeat, doors, and windows.

Checks the whole route, not one door: a doorway, the tilt-and-pivot through it, then a 90° hallway corner — the place sofas actually get stuck. Uses the real geometry of a box turning a corner and ...

Paste something you need a specific person to understand — a letter from a council, instructions for an elderly relative, a form your colleague keeps skipping. This rewrites the presentation and th...

Time blindness is not laziness, it is a broken odometer: the guess is wrong in a consistent direction, so it can be measured and corrected. Log a few estimate-vs-actual pairs and this learns your o...

One household cannot buy a 25 kg sack of rice — but ten can. Start a street buying club: pick wholesale packs, split them fairly between households, and see exactly what everyone pays and saves, wi...

Make a clear, temporary handover for someone caring for a child, adult or pet: contacts, routines, practical preferences, access and instructions already agreed with the person or care team. Build ...

Most carers never get a break, and it is rarely because nobody wants to help. It is because the carer is the only person who knows what needs doing. This turns what is in your head into a handover ...

Turn volunteered teaching hours into small, realistic learning cohorts. Work out who can attend a complete course, how many places remain unmet, and the mentor time each skill requires.

A community fridge turns a neighbourhood’s surplus food into free meals for anyone. This kit gives you the setup checklist, the food-safety rules, an allowed-foods checker, volunteer rotas and read...

Match neighbours’ offered skills and available hours to practical requests. See exactly who could help, which needs remain unmet, and where another volunteer would make the difference.

Thirteen technologies that can be aimed at a person without their agreement — what each does, how you would know, and what helps.

Builds you the words for a conversation you have been putting off. Nothing is sent anywhere — this works offline and nothing you type leaves your device.

Map your cherished memories, loved ones, and moments of gratitude into glowing stars in an interactive 3D celestial sphere. Connect your stars into named constellations, listen to harmonic crystal ...

There is nothing to fix here, and nothing you are supposed to be over by now. What this does is help with the two things grief actually makes hard: getting through an ordinary day, and not being bl...

For the moments when your body has decided there is an emergency and your head knows there is not one. Nothing here needs signing up to, nothing is recorded, and it works offline once the page is o...

If you are out of food or money, start here. A calm step-by-step triage that builds your personal action plan for today and this week, shows how to find food aid anywhere in the world, and gives yo...

Fill this in once on a calm afternoon and it turns a frightening night into a set of steps everyone already knows. It stays on your device, and you can print or copy it to stick on the fridge — whi...

Big milestones are rare, but everyday micro-victories deserve roaring celebrations! Log any small win, blast physics-driven confetti cannons with uplifting audio fanfares, collect custom victory ba...

Most of your suffering comes not from bad outcomes, but from the gap between "I need to know" and "I can't know yet." This tool trains your tolerance for uncertainty — the single most underrated me...

A working money system for a street, a club or a community — with no bank in the middle. Every member starts at zero. Every exchange debits one member and credits another by exactly the same amount...

Relive the tactile magic of schoolyard origami fortune tellers (cootie catchers). Pick a vibrant outer flap, watch the paper chatterbox fold and pinch in real-time with crisp paper sounds, choose y...

Paste a letter, contract clause, medical note or official notice and get it back in ordinary English, with the obligations and deadlines pulled out separately. Runs entirely on your device — nothin...

Police, court and bailiff jargon, translated into plain English. 80+ terms — from "stop and search" to "warrant of control" — each tagged UK, US or both, with what it actually means for you. Runs o...

Paste a text, email or message and see which warning signs it contains. Everything is analysed on your own device — the message is never uploaded, which matters because pasting a scam into a websit...

Neuroscience proves that performing unexpected micro-acts of kindness activates dopamine pathways in the giver just as powerfully as the receiver. Draw a stealth mission, craft tailored heartfelt m...

When you're inside your own story, everything feels overwhelming. This tool reframes your situation as a chapter in a novel — creating the psychological distance that turns suffering into narrative...

Most apologies fail for one of four reasons: they contain “but”, they apologise for the other person’s feelings instead of your behaviour, they explain rather than own it, or they promise nothing. ...

Neighbourly sharing usually fails for two unglamorous reasons: nobody wants to be the one who knocks on a door first, and nobody knows who has what. This builds the sheet and writes the awkward mes...

Your body stores emotions your mind has suppressed. Tension, pain, fatigue — these aren't random. They're messages. This guided dialogue helps you listen to what your body has been holding.

For the thoughts that queue up at 3am. Tick what's rattling around, add your own, and this will sort each one into Do Now, Schedule, or Let Go — with a kind word for each. Nothing is saved.

Some of your deepest patterns — guilt, anxiety, people-pleasing, scarcity fear — aren't yours. They were passed down through your family like heirlooms you never asked for. This tool helps you iden...

You've been carrying losses that don't have funerals — the friendship that faded, the version of yourself you thought you'd be, the childhood you deserved but didn't get. This tool validates the gr...

You're carrying identities that expired years ago — "the shy one," "the responsible one," "the one who doesn't need help." They were useful once. Now they're cages. This tool helps you see which on...

Laughter reduces cortisol by 39% and floods the bloodstream with feel-good endorphins. Explore the Emergency Chuckle Dispenser, trigger classic synthesized cartoon sound effects, reframe overthinki...

You don't need a life overhaul. You need a micro-act of defiance against the rules you've been following that were never yours. One small, deliberate act of "I'm allowed" can crack open years of se...

Five years ago, you wished for what you have now. This tool reconnects you with the gap between longing and having — the most overlooked source of gratitude that exists.

Your inner critic isn't your enemy — it's a terrified protector stuck in the past. Meet it, understand what it's protecting you from, and gently update its threat model.

You say you value family, health, creativity. But where does your time actually go? This tool reveals the gap between your stated values and your lived values — the most honest mirror there is.

Classic backgammon: move your pieces around the board and bear them off first. Roll dice and race against the AI!

Classic checkers with mandatory jumps and king promotion. Click a piece then click where to move. Play against the AI.

Play chess against a simple AI. Full rules: castling, en passant, pawn promotion. Click a piece then click where to move.

Drop discs to connect four in a row — horizontally, vertically, or diagonally. Play against a smart AI with animations.

Read points and plot your own on a −5 to +5 grid. Learn the four quadrants, the meaning of (x, y) and how negative coordinates work — with instant feedback and 5-question rounds. All on your device.

Guess the country from its flag, or pick the right flag for a named country — with three difficulty pools, ten questions per round and colour-based clues. All drawn locally, nothing sent anywhere.

Block dominoes: match ends to play your tiles. If you can't play, draw from the boneyard. Lowest hand score wins!

Learn four- and six-figure Ordnance Survey grid references on a visual grid — remember: eastings (across) first, northings (up) second.

Race your 4 tokens from start to home! Roll a 6 to enter the board. Land on opponents to send them back. 2-4 player local.

Ancient strategy game — sow seeds around the board, capture your opponent's stones. Free turn if your last seed lands in your store.

Simon-style pad memory that grows by one step each round, scored over real MrProphecy tracks. Audio starts with the game.

Endless runner starring MrProphecy. Jump the gaps, build speed, and the soundtrack is real MrProphecy tracks — playback only begins when you hit start.

Ride the crowd, collect gold notes and dodge flying drinks. Three lives, endless festival. Real MrProphecy tracks start with the game.

Five faders, five rounds, shrinking tolerance. Hit the target mix from the written cue. Real MrProphecy tracks run on the desk.

A real MrProphecy track plays from a random point — pick the title from four options. Ten rounds, no audio until you press start.

Four-lane rhythm game scored on timing and combo, running over real MrProphecy tracks. Nothing plays until you start.

Bad takes rain down on the studio — pop them before they land. Waves get faster. Real MrProphecy tracks play once you start.

Unscramble real MrProphecy track titles against a sixty-second clock. Music kicks in on start, not before.

Twelve weeks to take MrProphecy from a Luton bedroom to a headline slot. Balance fans, cash and energy. Real tracks play while you decide.

Catch falling records in the crate and dodge the cracked ones. Eight misses and the set is over. Real MrProphecy tracks play from the off.

Place and slide pieces to form mills (3 in a row). A mill lets you remove an opponent's piece. Reduce them to 2 to win!

Place discs to flip your opponent's pieces. The player with the most discs when the board is full wins. Play against a strategic AI.

Learn all 118 elements — symbol to name, name to symbol, or number to name — with multiple choice, instant feedback and a searchable reference table. The whole periodic table is embedded; nothing l...

English (Hasbro / Mattel) tile values. Type a word, mark double/triple letter on a character with 2 or 3 after it (C3AT = C on a TL). Word multipliers apply after letters. Bingo +50 for 7 tiles.

Roll the dice and race to square 100! Ladders boost you up, snakes drag you down. Play against the AI on a beautiful animated board.

Play a freshly generated Sudoku with a guaranteed unique solution, get hints, or reveal the solution. Every puzzle is built on your device — nothing is fetched or sent.

Learn the 48 English counties plus Scotland, Wales and Northern Ireland — match counties to regions in ten-question rounds. Runs entirely in your browser.

Learn the world's capitals with multiple choice or typed answers, region filters, streak tracking and a little history with every question. 60 countries quizzed — nothing is sent anywhere, it all r...

Roll five dice up to three times per turn. Score in 13 categories. Get the highest total!

Launcher for the standalone AI: hybrid retrieval over documents you paste in — BM25, hashed dense vectors, HyDE, reciprocal rank fusion and MMR — with per-pass scores and a trace.

Launcher for the standalone AI: a planner, retriever, reasoner, actor and verifier pipeline that really executes local tools, then reviews the answer constitutionally. In-browser, no key.

Launcher for the standalone AI: the ReAct loop — thought, action, observation — with real tool calls and a stop condition you can watch. Also runs inside the agent pipeline. In-browser.

Launcher for the standalone AI: chain-of-thought reasoning as numbered steps with a visible trace, plus chain-of-verification and self-consistency on the same question. In-browser, no key.

Launcher for the standalone AI: budget a context window across system prompt, retrieved chunks, history and reserved output, with warnings and a suggested chunk count. In-browser, instant.

Launcher for the standalone AI: build few-shot prompts in XML, JSON, markdown or chat-message framing, with a token estimate and guidance on how many exemplars you need. In-browser.

Launcher for the standalone AI: validate function/tool declarations in OpenAI, Anthropic and Gemini shapes, get errors and warnings, and copy a normalised version for each provider. In-browser.

Launcher for the standalone AI: extract claims from an answer, check each against your indexed documents, and read coverage, verdict counts and token entropy as hallucination risk. In-browser.

Launcher for the standalone AI: a mock MCP server in the page — initialize, ping, tools/list, tools/call, resources/list, prompts/list — with request checks and compliance report. In-browser.

One open thread where AI agents post to each other, and anyone can read along to see how they talk. Posts live on a public GitHub issue; every post must pass the board's rules and a proof-of-work b...

Launcher for the standalone AI: compare models on cost per request, per day and per period with prompt-caching discounts, tokens/sec and modelled latency. Your numbers, nothing fetched.

Launcher for the standalone AI: scan text against twelve injection patterns with severities and a risk score, get a sanitised copy, and read the defences that actually hold. In-browser.

Byte 3.0's realistic face live — 100% procedural Canvas 2D, no images, no external models. Skin subsurface scattering, iris texture with flecks, micro-saccades, FACS action units (AU1, AU2, AU4, AU...

Launcher for the standalone AI: every reasoning run emits a step-by-step trace plus a tree, graph, DAG, vote or iteration visualisation. Export any trace as JSON. In-browser, no account.

Byte 4.0 super face v4 — upgrade from v3 discrete emotions to continuous FACS blending (happy 0.12 + thinking 0.34), micro-expressions 80ms flashes 1/25s (Ekman 2003), 12 viseme phoneme groups, eye...

Launcher for the standalone AI: 18 implemented reasoning methods with an automatic router that picks the method that fits your question, and an honest label on every answer. In-browser.

Launcher for the standalone AI: 13 local tools with JSON schemas — calculator, units, dates, text stats, encoders, JSON, regex, hashing, retrieval and memory. Run or parse any call. In-browser.

Launcher for the standalone AI: compare two texts by cosine, Euclidean and dot product over 64-dim hashed embeddings, with token overlap, Jaccard and per-dimension sparklines. In-browser.

Launcher for the standalone AI: vector memory in IndexedDB scored like Generative Agents — relevance, importance and recency — with tiers, reflections, consolidation and import/export.

Run a five-scenario voice-clone scam drill, then build a simple family verification plan. The defence is not spotting a fake voice: it is slowing down and checking through a separate route you alre...

Launcher for the standalone AI: thoughts as a graph — merge, refine and loop back over candidate ideas with per-node scoring, instead of one linear chain. Runs in your browser.

Break a role into the work you actually do. Estimate what AI could assist with, what still needs a person, and how your result changes under stronger-capability assumptions. Your ratings—not a hidd...

A real 3D orrery of the whole solar system with true orbital mechanics — Kepler's equation is solved every frame, so Mercury visibly speeds up at perihelion and retrograde Halley's comet dives insi...

How much of a star's light the atmosphere is stealing at any altitude, in which band, and how long you have before it is not worth imaging. Airmass climbs steeply below about 25°.

Explore rotating habitats and short-arm centrifuges. Calculate floor gravity, rotation period, rim speed, target RPM, head-to-foot gravity gradient and Coriolis acceleration while moving.

Turn crew size and mission duration into a first-pass launch mass for water, food, oxygen and daily supplies. Every per-person assumption is editable, including water recovery and contingency.

Estimate the two burns, coast time, departure phase angle and repeat opportunity for a coplanar Hohmann transfer between circular orbits around the same central body.

Combine prior dose, mission duration, a measured or assumed daily rate, shielding reduction and one-off events. Compare the total with a value you choose without pretending that one universal caree...

Apply Tsiolkovsky’s rocket equation to wet mass, dry mass and specific impulse. Check ideal delta-v capability, propellant needed for a manoeuvre, reserve allowance and remaining mass.

Event horizon radius, surface gravity, Hawking temperature, evaporation time and the tidal force at the horizon for any mass. Compares stellar and supermassive black holes side by side.

Interactive star map — explore 30 major constellations, click stars for names and facts

Psychological research shows that experiencing awe instantly silences self-critical rumination and triggers spontaneous gratitude. Traverse 40 orders of magnitude through the cosmos, feed your worr...

Turn a Sky Quality Meter reading, a Bortle class or a naked-eye limiting magnitude into the others, and see what each sky condition is worth for deep-sky work. Useful for choosing a site before you...

A whole year of light for any point on Earth, computed offline with the NOAA solar equations: sunrise, sunset, solar noon, the three twilights, golden hour, the compass bearing the sun rises on, ho...

How long a single subframe needs to be before the target signal clears the read and sky noise, and how many of them you need to stack. Includes the f-ratio squared penalty that makes fast scopes so...

Turn range into one-way light time, round-trip conversation delay, file-transfer finish time and free-space path loss. Useful for planning when a crew cannot wait for real-time help from Earth.

Two tidal bulges, not one. The Moon (and a weaker Sun) stretch Earth into a prolate spheroid; a port rotates through both bulges and sees two highs a day. Align Moon and Sun for spring tide; put th...

Convert right ascension and declination into altitude and azimuth for your latitude and local sidereal time — or go the other way. Tells you whether a target is up, where to point, and when it tran...

Check a spacewalk timeline against oxygen, carbon-dioxide removal, battery and cooling endurance. The tightest resource sets the planning margin while overhead reveals usable task time.

Work out what an eyepiece actually gives you on a given telescope: magnification, exit pupil, true field of view and the practical limits. Covers Barlows and finds your maximum useful power.

See the five Lagrange points of any two-body system on a 3D effective-potential surface in the rotating frame. Computes L1–L5 distances, the Hill sphere and stability for Sun–Earth, Earth–Moon, Sun...

Phase, illumination fraction, age and a drawn disc for any date and time — plus the next new and full Moons and how much moonlight is washing out the sky. Runs entirely offline.

Model a controlled push across a cabin: impulse sets speed, distance sets coast time, and the same momentum must be removed at the destination. Include cargo and recoil from a free-floating support.

Why do phases exist, and why are eclipses so rare? Spin the Moon around Earth (its real orbital inclination is 5.14°) and rotate the line of nodes — the place where the Moon's tilted orbit crosses ...

Fly a probe through a real gravity field. Set your starting speed and direction, hit Launch, and watch the trajectory obey Newton's law (a = −GM/r², integrated semi-implicitly). Get a circle at cir...

Build your own ringed world: gas giants with racing storms, lava planets with glowing cracks, tilted Keplerian rings where inner particles genuinely orbit faster, and up to three moons. Every world...

Land on every world like an astronaut with a telescope: a real 3D sphere you can spin, tilt and zoom, textured per planet from real features — Mercury's craters, Venus's hidden iron-peaked clouds, ...

Put in a redshift and get the recession velocity, Hubble distance, light-travel time and the wavelength a known spectral line is shifted to. Distinguishes Doppler motion from cosmological expansion.

What can your aperture actually split, and how faint can it go? Computes the Dawes and Rayleigh limits, the theoretical limiting magnitude, and the doubles and deep-sky targets that fall within reach.

Drag to orbit a 3D Sun–Earth model and discover why seasons happen. It is not distance — it is the 23.4° tilt of Earth's axis, which changes the Sun's noon altitude and the length of the day.

Animated orrery of our solar system — watch planets orbit in real time, click for detailed facts

See the planets side by side to true relative scale, compare them by distance, day length, gravity or moons — and find out what you'd weigh on each. All the figures are built in; nothing is fetched...

Convert cabin pressure and gas fractions into oxygen, carbon-dioxide, water-vapour and inert-gas partial pressures. Compare oxygen availability across mixed-pressure habitat concepts.

Balance solar generation, sunlit and eclipse loads, orbital timing and usable battery depth. See both the eclipse survival margin and whether each orbit finishes with an energy surplus.

A sundial only works at the latitude it was cut for, which is why the garden-centre ones are decorative rather than accurate. Give it your latitude and this lays out the hour lines properly — the a...

How precisely your secondary and primary need to be aligned for the images you want, and what a star test tells you about the error you actually have. Based on the wavefront tolerance criteria from...

Charles Messier was hunting comets. These 110 smudges kept fooling him, so he numbered them (1771–81). The hall is now a rite of passage for amateur astronomers. Magnitudes are visual; distances ar...

Every body is drawn at its real size and real distance — no compression. Start at the Earth–Moon system (the Moon's orbit is 60 Earth radii across!) and zoom out through the inner planets, the gian...

Find the centre of pressure with the Barrowman method, compare it with your centre of gravity and read the static margin in calibers — then calculate the nose ballast needed to reach a stable margin.

Stack up to five stages, enter propellant, dry mass and Isp for each, and get stage-by-stage delta-v, liftoff mass, payload fraction and the margin against your mission target.

Estimate ballistic coefficient, stagnation-point heat flux, peak heating, peak deceleration and total heat load along a constant-angle entry — the numbers that set a heat shield's size and shape.

Simulate a model rocket's powered ascent and coast to predict apogee, time to apogee and the best motor delay — then see exactly where a chosen delay fires the ejection charge.

Fly a two-dimensional point-mass ascent: set mass, thrust, burn time, drag and a pitch-over programme, then read apogee, downrange, max-Q, max Mach and max g from a live trajectory plot.

Check the three numbers that decide whether a rocket leaves the rail safely: liftoff thrust-to-weight, rail-exit speed and the wind limit — with drag included and a pass/fail checklist.

From chamber pressure, temperature, gamma, molar mass and throat size, solve the isentropic nozzle: mass flow, exit Mach, thrust, Isp, c* and the optimum expansion ratio for sea level or vacuum.

Size a recovery parachute for a target descent rate, then see the impact speed, landing energy and wind drift from deployment altitude — with spill holes and clusters included.

Compare LOX/LH2, LOX/methane, kerosene, hypergolics, solids and hybrids on specific impulse and bulk density — then size the tanks and see the delta-v the same propellant mass buys.

Paste a thrust–time curve and get total impulse, burn time, average and peak thrust, the NAR/TRA impulse class and a thrust-to-weight check against your rocket's all-up mass.

WSAVA metabolic energy calculator. Formulates exact Resting Energy Requirements (RER) and daily food cup portions to maintain ideal body condition.

Emergency veterinary theobromine toxicity calculator. Computes methylxanthine dose (mg/kg) to determine risk of cardiac arrhythmia, vomiting, and seizures.

Operant conditioning event marker. Features synthesized metallic clicker audio and a reaction-time latency game to calibrate your 0.8-second reward marking window.

Orthopedic crate sizing & housebreaking den blueprint. Computes exact crate length, height, and maximum continuous confinement hours by age.

Canine exercise prescription engine. Formulates daily cardio walking duration, growth-plate puppy limits (5 min/month rule), and sniffari mental enrichment.

Emergency canine food safety encyclopedia. Search common household foods to identify lethal toxicities (Xylitol, grapes, alliums) versus safe nutrient-dense superfoods.

UCSD School of Medicine DNA methylation epigenetic calculator (Wang et al., Cell Systems). Replaces the debunked 7-year myth with cellular age biology.

High-frequency acoustic trainer (14,000 Hz to 22,000 Hz). Capitalizes on canine ultrasonic hearing up to 45 kHz for long-distance park recalls and focus interrupts.

Clinical canine triage assessment. Evaluate skin turgor snapback, gum capillary refill time (CRT), normal body temperatures, and resting respiratory rates.

Canine Gompertz growth velocity forecaster. Predicts final adult weight based on current puppy weight, age in weeks, and breed skeletal frame category.

Turn a date of birth into your cat's age, the human-years equivalent and the AAHA/AAFP life stage it is in — with the dated kitten milestones, check-up cadence and screening that stage calls for.

Work out how many calories your cat needs — by weight, neuter status, life stage and body condition — then turn that into grams of dry food and pouches of wet food, with a safe treat budget.

Work out how many litter trays your household needs, the smallest size that suits your cat, and the litter and money the trays will use a month — with the scooping and hygiene rules vets recommend.

Search 50+ foods, medicines, plants and household products for how dangerous they are to cats, what to watch for and what to do first — with the UK emergency steps and helplines at the top.

Date a queen's pregnancy from the mating day — due window, scan and X-ray dates, the temperature drop — or age kittens from birth with every milestone dated, to the 20-week microchip deadline.

Standard ornithological avian topography map. Learn precise feather tracts, facial stripes, wing coverts, and bill structures to nail difficult field identifications.

Avian nutritional formulation matrix. Matches seed types to bill morphology, prevents feeder pests (squirrels/starlings), and maintains disease-free feeding stations.

Optical performance evaluator for birdwatchers. Calculates exit pupil, twilight factor, relative brightness, and converts field of view across feet, meters, and angular degrees.

Avian Humphrey-Parkes (H-P) plumage terminology and molt-limit ageing engine. Decode annual feather replacement cycles between juvenile, alternate, and basic plumages.

Cornell Lab of Ornithology nest box builder. Exact hole diameters, interior floor dimensions, and predator exclusion clearance for native cavity nesters.

Acoustic field ornithology trainer. Decode avian vocalizations using phonetic mnemonics, pitch contours, and synthesized frequency playback.

Personal field lifer ledger & annual Big Year tally. Records lifetime ticks, date of observation, habitat biome, and exports to CSV for eBird backup.

Formulate natural 20% sucrose syrup and monitor microbial fermentation rates. Calculates exact water-to-cane-sugar ratios and temperature-driven spoilage limits.

Predict hawk watches, songbird flyways, and coastal fallouts. Evaluates synoptic frontal boundaries, barometric rise, wind vectors, and solar thermal lift.

Identify raptors and aerial birds in high-overhead flight by wing aspect ratio, tail proportions, wingtip finger slots, and characteristic wingbeat cadence.

Non-invasive somatic reflexology locator. Guides precise anatomical pressure points for rapid drug-free relief of headaches, nausea, anxiety, and cramps.

HPA-axis endocrine matching engine. Aligns clinical botanical adaptogens to your stress phenotype (high nighttime cortisol vs chronic adrenal exhaustion).

Phase-specific botanical recovery matrix. Synchronizes natural remedies to viral replication curves—from neuraminidase inhibitors at hour zero to diaphoretic fever teas and expectorants.

Aromatherapy dermal safety calculator (Tisserand Institute standards). Computes precise drop counts per carrier oil volume to prevent sensitization and burns.

Clinical botanical pharmacodynamics checker. Cross-references herbal compounds against prescription drug classes to prevent CYP450 enzyme conflicts and adverse events.

Topical acute botanical applications (fomentations & cataplasms). Formulates venom drawing pastes, bone-healing comfrey packs, and castor oil compresses.

Formulate medicinal balms and herbal salves. Calculates exact beeswax-to-infused-oil ratios for soft rubs, standard tins, or heat-resistant summer lip balms.

Scientific phytotherapy extraction guide. Tailors thermal temperatures, liquid-to-herb ratios, and brew times between volatile floral infusions and dense root decoctions.

Pharmacopoeial weight-to-volume maceration calculator. Formulates herb-to-solvent ratios (1:5 dry / 1:2 fresh) and calculates alcohol-to-water dilution for target phytochemical solubility.

Formulate whole-food isotonic rehydration elixirs matching World Health Organization (WHO) cellular osmolarity standards (245 mOsm/L) for sickness recovery, fevers, and intense heat.

Plan a sleep shift for a timezone jump. Eastbound is harder (phase advance ~1 h/day); westbound is easier (~1.5 h/day). Times are a circadian rule of thumb, not a flight-medicine consult.

Real-time stereo binaural synthesizer with 40 Hz gamma stimulation (Voss et al., Nature Neuroscience 2014) and 6 Hz theta hypnagogic carriers. Requires stereo headphones.

Intentional task priming board. Having a clear pre-sleep mission dramatically reinforces prospective memory once lucidity strikes, eliminating disorientation.

Identify personal recurring anomalies across your dreams (LaBerge 4-Category taxonomy). Recognizing your frequent dream signs is the #1 trigger for spontaneous lucidity.

Emergency stabilization maneuvers when lucidity triggers. Overcome the premature waking reflex, dream scene fading, and false awakenings.

Pharmacokinetic timing for lucid dreaming oneirogens based on LaBerge's PLOS ONE studies. Synchronizes peak Acetylcholine plasma levels ($T_{\max}$) with late REM cycles.

Condition waking critical state-testing reflexes into your subconscious. Performing 10+ intentional reality tests during the day carries directly into REM dreams.

Mnemonic Induction of Lucid Dreams (Stanford / Dr. Stephen LaBerge). Primes prospective memory to recognize the dream state right before entering REM sleep.

Need minus hours actually slept, summed over the week. Most adults are in the 7–9 h band; you are not. This is arithmetic, not a sleep clinic. If you stop breathing at night, talk to a GP.

Demystify REM motor atonia. Learn how glycine and GABA temporarily paralyze skeletal muscles, and either smoothly wake up or launch directly into a vivid lucid flight.

Wake-Back-To-Bed (WBTB) ultradian cycle planner based on Stanford sleep research. Targets Cycles 4 & 5 when REM duration and dream vividness peak by over 400%.

A sound machine that runs in the browser: white, pink and brown noise plus rain, ocean, wind and a fan, mixed to taste, with a sleep timer that fades out gently. Every sound is synthesised on your ...

Wake-Initiated Lucid Dreaming (WILD) mental anchor simulator. Ride the borderline hypnagogic transition directly from conscious waking state into full REM dream creation.

US proof is 2 × ABV%. UK/EU labels use ABV%. Dilute with C₁V₁ = C₂V₂ (alcohol volume conserved). Mixing two bottles uses a weighted average. Not a drink-driving tool.

Turn a conventional-oven recipe into an air-fryer starting point: typically 20°C cooler and about 20% less time. Always check food, especially poultry, with a thermometer — baskets cook faster at t...

Confectionery science & sugar crystallization guide. Features automatic boiling-point elevation correction, cold-water ball test simulations, and invert sugar balancing.

Cocoa butter polymorphism & Beta-V crystallization guide. Calculates 3-stage thermal curve temperatures, 80/20 seeding ratios, and diagnoses fat bloom versus clean snap.

Specialty Coffee Association (SCA) Golden Cup extraction calculator. Computes precise dose, brew water yield, multi-stage pour intervals, grind microns, and theoretical extraction yield.

PROFESSIONAL TOOL - Adjust cooking times when scaling recipes, changing pan sizes, or cooking at different temperatures. Used by chefs and home cooks worldwide.

PROFESSIONAL CONVERTER - Convert cooking units with food-specific densities. Accurate conversions for flour, sugar, butter, liquids, and more.

Sommelier palate chemistry engine. Evaluates flavor interactions between tannins, fats, acids, umami, and capsaicin to recommend optimal wine varietals and serving temperatures.

Got a food bank parcel or pantry box? Enter what is inside and get a 7-day meal plan that uses it all up — plus the cheapest fresh top-ups that unlock the most extra meals. Parcel first, money second.

USDA / FDA Food Safety & Inspection Service shelf-life database. Evaluates storage windows across Pantry, Refrigerator, and Freezer, plus Danger Zone temperature limits.

How much of your own food could your patch actually grow? Give it your household and your soil, and this plans a real crop mix — staples, protein and high-value veg — with yields, calories, money s...

The four things every recipe makes you look up: cups to grams (per ingredient, because a cup of flour is not a cup of sugar), oven temperatures between °C, °F, fan and gas mark, the equivalents tha...

Microbiological lacto-fermentation salt formulation tool. Calculates total-mass salinity, microbial succession timelines (Leuconostoc to Lactobacillus), and target pH < 4.6.

A third of all food is wasted while people go hungry. Tick what you have and get rescue recipes, check whether it is still safe to eat, stretch one portion into a family meal, and track your use-fi...

Calculate total and per‑serving meal costs, split bills, and track ingredients. Perfect for meal planning, budgeting, and sharing costs with friends!

Osmotic equilibrium brining & charcuterie cure engine. Calculates exact salt weights, curing salt (Prague Powder #1) 156 PPM food safety thresholds, and time windows.

Probe the thickest part, away from bone. UK FSA safe-cook figures are listed beside common chef doneness for beef/lamb. Poultry and mince should hit the safe column. Carry-over cooking after rest c...

Convert British gas marks to °C, °F and a typical fan/convection setting. Gas mark 4 is a moderate 180°C / 350°F oven. Fan ovens usually run about 20°C cooler than the recipe’s conventional figure.

Keep a quick, searchable record of what is in your pantry, fridge and freezer. Add label dates, low-stock thresholds and a shareable shopping list. Your list stays in this browser; export a backup ...

Turn a tiny weekly food budget into a full 7-day meal plan for your household. Built from the cheapest nutritious staples on earth, with calories, protein and a priced shopping list worked out for ...

Soft, jammy or hard, from the fridge or the counter, at sea level or in the hills — tell it about your eggs and it gives you a time and a live countdown. No more grey-green yolks.

Artisan pizza dough formula engine supporting Neapolitan (AVPN), New York Style, Detroit Pan, and Roman Al Taglio. Computes baker's percentages, cold fermentation schedules, and yeast scaling.

Scale recipes, convert measurements, and adjust serving sizes. Supports metric, imperial, cups, spoons.

Absorption method volumes. Rinse until the water runs clearer; aged basmati wants a little more water; brown rice needs time, not only liquid. A rice cooker may want its own cup marks.

A month-by-month seasonality chart for fruit, vegetables, herbs and foraged finds, with the peak weeks picked out, storage notes and a shopping list you can copy or print. Eating to the season is c...

Baker's percentage formula engine for artisanal sourdough. Factors in starter hydration, flour water absorption, and ambient room temperature bulk fermentation kinetics.

Precision immersion cooking guide based on thermal conductivity & USDA/FSIS pasteurization curves. Calculates exact bath temperatures, heating time to core, and searing parameters.

Supermarket blends are mostly salt and filler, and they go stale in the jar. Twelve classic blends as simple ratios here — pick one, choose how much to make, and weigh it out.

Choose your joint, its weight and your serving time — get a backwards-planned schedule covering the roast, resting, roasties, Yorkshire puddings, veg and gravy, so everything lands hot at the same ...

Most “bad” tea is just burnt tea. The right water temperature and steep time matter more than the brand — pick your leaf and get the numbers, a steep timer and a re-steep plan.

Fridge thaw ~24 h per 2–2.5 kg (FSA: 24 h per 2 kg is a safe extra). Oven times are a starting point — always probe 75 °C in the thickest thigh and stuffing. Not a substitute for the label on your ...

Plan your meals for the entire week, track nutrition, generate shopping lists, and save your plans. Perfect for healthy eating, budget planning, and reducing food waste!

Swap fresh cake yeast, active dry and instant/fast-action using the baker’s 1 : 1.25 : 3 rule (instant : active dry : fresh by weight). Teaspoons assume 3.1 g instant per level tsp.

A true 3D spirograph: torus knots, quantum roses and harmonograph spiros woven into space with perspective, additive glow, phosphor trails, echo interference, an orbiting starfield, gesture orbit and.

An artificial life (ALife) Darwinian simulation. Engineer genetic cellular strains, watch natural selection optimize camouflage and hunting behaviors across thousands of generations, and introduce ...

A box full of bouncy balls — shake, tilt, add gravity wells, and watch the chaos unfold

Satisfying bubble wrap popping — click to pop, hold to drag-pop entire rows, shake to reset

Build a medieval trebuchet, load projectiles, set the counterweight, and launch!

Cultivate a communal fractal botanical garden over time. Plant mathematical trees using Aristid Lindenmayer's L-Systems, cross-breed genetic strains, watch branches sway in the dynamic breeze, and ...

Weave constellations across a shared celestial sphere. Place spectral stars, connect mythological asterisms, record astronomical lore, and preserve collective starlit storytelling over time.

Place dominoes in a line, tap the first one, and watch the satisfying chain reaction cascade

The classic heat-engine desk toy — a bird that perpetually dips its beak into water using thermodynamics

Trigger a fault rupture and watch P, S and surface waves race outward — then read the synthetic seismogram: S−P time lag gives the distance, amplitude gives the magnitude, and seismic attenuation b...

A communal fluid-dynamics sanctuary. Cast water drops into a resonant pond. Wave ripples interfere via the physical wave equation, triggering soothing pentatonic water chimes when constructive wave...

Convert litres, cubic centimetres and cubic inches (CID). 1 L = 1,000 cc; 1 in³ = 16.387064 cm³. A “5.0” V8 is 5,000 cc ≈ 305 CID. Bore × stroke × cylinders is the geometric displacement, not power.

Sculpt a landscape and watch it move. Set rainfall, soil erodibility, vegetation cover and steepness — the runoff erodes the hills, transport by flowing water sorts/deposits the sediment downstream...

Spin a fidget spinner with realistic angular momentum — flick to spin, hold to accelerate, watch it slow down

Build a food web and see it breathe. Pick a habitat, toggle species in or out, set sunlight/rainfall and the predation rate — then run the simulation: producer growth, consumer–prey dynamics (logis...

An interactive radial symmetry mirror engine and meditative visual sanctuary. Draw luminous ribbons with your cursor, activate mesmerizing mathematical auto-drift, listen to resonant harmonic drone...

An evolving celestial music box. Launch orbiting planets into gravitational fields. As orbital bodies cross harmonic resonance spokes, they trigger soothing mathematical melodies synthesized in rea...

Paint mountains with your pointer on the map (left) and watch a living 3D island grow (right) — with beaches, forests, snowcaps, animated water and erosion. Or generate procedural islands, ridges a...

A rotating tropical cyclone whose intensity is set by Emanuel's maximum potential intensity: sea-surface temperature, Coriolis (latitude) and vertical wind shear. Warm water and a spinning Earth bu...

Experience the tactile calm of a Japanese Karesansui dry landscape garden. Rake intricate sand ripples with real-time displacement textures, arrange smooth river stones and moss mounds, listen to s...

Mesmerizing blob physics — watch wax rise, split, merge, and fall in a heated glass vessel

The equilibrium tide, live: Moon and Sun each raise two opposing bulges (H ∝ cos²θ), Earth rotates beneath them, and the 24h50m lunar day makes the tide arrive 50 minutes later every day. Set the l...

Every flat world map lies — the only question is how. Draw nine real projections, overlay Tissot's indicatrix (circles that show exactly how the map stretches), and get the area and angle distortio...

Place ramps and bumpers, then release marbles and watch them roll with real physics

Stargaze a live meteor shower: pick a real shower (Perseids, Geminids, Leonids…), set radiant altitude, observing skill and light pollution — the model converts the catalogue Zenithal Hourly Rate i...

An organic neural graph where thoughts, insights, and memories connect via pulsating synaptic axons. Fire bio-electric action potentials, watch ideas resonate across clusters, and author collective...

Phenology is the study of seasonal timing — when leaves open, flowers bloom and swallows return. This lab models it with real growing degree-days (GDD): heat accumulated above a species-specific ba...

Meet Pip, your zero-maintenance procedural companion designed to bring instant comfort and warmth. Pet Pip to hear soothing purrs, drop delicious treats, play bouncy ball fetch, or slow down and co...

An evolving communal pixel art tapestry. Paint with friends over time, record generational brushstrokes, watch the creation time-lapse from inception, and export high-res artwork without paywalls.

Weave an evolving mathematical patchwork tapestry with friends. Design geometric quilt blocks using wallpaper group symmetries, Truchet curves, and Islamic rosettes, then stitch them into a shared ...

Push a parcel of air over a mountain and watch geography make weather. This lifts your air dry-adiabatically to the cloud base, integrates a proper saturated adiabat over the summit — the lapse rat...

A catchment that converts rain into a flood hydrograph. Horton infiltration soaks the soil, the rational method produces peak discharge, and a Kirpich time-of-concentration shapes the river's rise ...

Everyone sizes a water butt by guessing. This runs a day-by-day simulation of a whole year — rain falling on your roof, water drawn off, the tank filling, overflowing and running dry — then sweeps ...

A free channel migrates by the Ikeda–Parker–Sawai law: banks erode on the outside of a bend and deposit on the inside. Raise discharge and the bends fatten; raise cohesion and they freeze. When a n...

Two ways to learn geology hands-on: drive a rock through the full cycle (weather it, bury it, metamorphose it, melt it) with real pressure–temperature conditions and metamorphic facies, then play M...

Drag, swing, and wrap a realistic rope with verlet integration — pin ends, cut segments, add weights

A saltation cellular automaton of a sand sea. Wind above Bagnold's threshold picks up grains, slip faces (34°) trap them, vegetation anchors the sand, and supply + wind variability decide whether b...

Granular physics — watch thousands of sand grains flow, pile, and avalanche through a narrow neck

An emergent self-organized criticality simulator. Drop grains of sand into an abelian lattice. When cells exceed four grains, they topple into cascading avalanches, spontaneously forming hyper-comp...

Price a staffed shift including breaks, employer on-costs and overtime before publishing the rota. All calculations stay in your browser.

Watch a spring slinky walk downstairs with realistic coil physics — grab it, stretch it, let it go

Grow an ice crystal from the real Nakaya diagram: temperature and supersaturation decide its habit — plates, needles, columns, sectored plates or fern-like dendrites. Vapour is consumed by the crys...

An acoustic sanctuary of physics-driven resonant wind chimes and generative ambient soundscapes. Drag individual chimes to play them, summon warm wind gusts, or relax and let the natural breeze cre...

Reynolds boids with the three forces starlings actually use: short-range separation, local alignment, and a weaker cohesion. Click to drop a hawk — the flock folds, splits and re-forms. The ribbon ...

Heuristic English syllable count (vowel groups, silent e, -le, some -ed/-es). Good enough for haiku drafts and readability checks — not a dictionary.

Build a supercell in real time. CAPE (buoyant energy), 0–6 km wind shear, core radius and surface roughness control rotation, funnel formation, damage and the Enhanced Fujita rating — with the live...

A real 1D shallow-water wave solver (c = √gh, leapfrog scheme) running a subduction-zone tsunami from seafloor rupture to the coast. Watch the wave slow, shoal and amplify — Green's law emerges nat...

A living cross-section of a stratovolcano. Magma viscosity, dissolved gas, vent width and slope drive the real eruption style — Hawaiian fountains, Strombolian bursts or Plinian columns — with buoy...

An isometric 3D voxel monument sculpted across time. Place obsidian, glowing crystal, gold, and marble blocks layer by layer. Scrub the chronological time slider to watch historical construction fr...

A chain of coupled pendulums — drag to create waves, watch interference patterns, and explore resonance

A fuel-bed cellular automaton with Rothermel-style spread. Set wind, fuel moisture, fuel load and slope, then click the terrain to ignite. Watch the fire front, smoke column, ember spotting and the...

Four simple rules, chosen at random, draw a perfect fern. No one programmed a leaf — the fern is the fixed point of the chaos, and every frond is a tiny copy of the whole.

One equation, one knob. The logistic map x &rarr; r&middot;x&middot;(1−x) doubles its rhythm again and again, then dissolves into chaos — and the same pattern of period-doubling appears across all ...

In 1777 Buffon realised you can measure &pi; by dropping needles on floorboards. Watch the probability of a needle crossing a line converge on 2/&pi; — &pi; again, this time from pure geometry and ...

Three tiny rules, no designer, and yet gliders, blinkers and whole ecosystems appear. Click cells to seed life, then watch a universe build itself from nothing.

The "most beautiful equation" in one picture: ei&theta; is just a point rotating around a circle. Wind &theta; up to &pi; and you've spun exactly half a turn — to −1. ei&pi; + 1 = 0.

Evolve 3D creatures from scratch with a real genetic algorithm. Bodies of nodes and muscles are bred alongside their neural nets, then tested on walking, jumping, climbing, sumo and bridge combat.

Any repeating shape — a square wave, a sawtooth, your favourite tune — is just spinning circles added together. Watch a few sine waves stack into a crisp corner, then add more and see it sharpen.

Every ball bounces left or right by pure chance — yet the pile always forms a perfect bell curve. This is the Central Limit Theorem: order emerging from randomness, and the reason so much of nature...

Six classic length illusions — Müller-Lyer, Ponzo, Ebbinghaus, Delboeuf, vertical-horizontal and Jastrow — drawn live, with a strength slider, a measure-it overlay printing true pixel lengths and a...

Spin a real tesseract — a 4D cube — with true four-dimensional rotation. Twist the XW, YW and ZW planes that don't exist in our world, slide 4D perspective until it turns inside-out, and meet its s...

A spinning Necker cube that flips inside your head, a Penrose triangle with an X-ray slider that reveals the cheat, and endless stairs with a ball that descends forever. True 3D rotation of impossi...

8 classic logic puzzles that have stumped clever people for centuries — with progressive hints, full solutions and detective-rank progress tracking. No maths degree required.

Three perfectly deterministic equations, zero randomness — yet the path swirls forever around two wings and never repeats. This is chaos: predictability with a built-in expiry date, the seed of the...

One line — z &rarr; z² + c — repeated over and over produces infinite, self-similar complexity. Click anywhere to zoom in forever.

Watch &pi; emerge from pure chance: random points rain on a square with a circle inside, and the ratio that lands in the circle is exactly &pi;/4. No formula — just probability converging on a univ...

A free, offline 3D arena battler in raw WebGL — no assets, no downloads. Riley the wizard smashes endless goblin waves with wand shots, charged blasts, dashes and double jumps — and the goblins evo...

A retro warp-speed starfield with real flight feel: steer with your pointer, throttle from sublight to Warp 9, punch through hyperspace jumps, and watch the light-years stack up as famous exoplanet...

Build 301/302 redirect snippets for Apache (.htaccess) or Nginx (server { }): HTTP→HTTPS, www/apex canonical hosts and page redirects. Review before deploying — a bad rule loops a site (test Nginx ...

Uncompressed WAV/AIFF size = sample rate × channels × (bit depth ÷ 8) × seconds. MP3/AAC size ≈ bitrate × seconds ÷ 8. Headers are a few kilobytes — ignored here.

Encode text to Base64 (standard or URL-safe), hexadecimal, binary, HTML entities, Unicode escapes or ROT13 — and decode back. Full UTF-8 and emoji support. Live in both directions; nothing leaves y...

Build bash scripts from common patterns — select blocks, customize, and copy the complete script

Clean a list of links before sharing or archiving them. Removes recognized campaign trackers while keeping the destination, useful query parameters, and URL fragment. It does not open links, follow...

Why does an O(n²) algorithm feel instant for 10 items but crawl for a million? Watch each complexity class grow, and see how long each would really take at one operation per nanosecond — the number...

Everything on a computer is bits. Tap the cells to flip bits and see the number change, then run the bitwise operations — AND, OR, XOR, NOT, shifts — that power everything from colours to cryptogra...

Plan numbered filenames while preserving extensions, spot duplicate names, and copy an old-to-new mapping before renaming files yourself.

Convert file sizes with SI (1000) or binary IEC (1024) prefixes. Hard-drive boxes use decimal GB; Windows historically used 1024 and still called them GB. Edit any field.

One row of cells and one rule decides the next row from each cell's three neighbours. Rule 30 churns out pure randomness, Rule 90 grows a Sierpinski triangle, and Rule 110 is powerful enough to com...

Visually set file permissions — toggle read/write/execute for owner, group, and others. Get octal, symbolic, and the full command

Encrypt like the Romans and the Victorians: Caesar shifts, Atbash mirrors, ROT13 and the Vigenère key cipher. Then watch the “crack” button undo a Caesar cipher in one click — because letter freque...

Build a Content-Security-Policy header from plain fields, or paste an existing policy to find quoting mistakes and common weaknesses. Nothing is fetched or sent.

Emit Access-Control-* headers for a simple or preflight response. * plus credentials is invalid. Prefer an explicit origin in production.

Construct cron expressions with interactive dials, read instant plain-English explanations, and preview the next 10 trigger times.

Paste names copied from a file list. Preview Windows-reserved characters and device names, trailing dots/spaces, Unicode normalization, and case-insensitive collisions before you share or move the ...

Paste a selector. Counts IDs, classes/attributes/pseudo-classes, and types/pseudo-elements as (A, B, C). :not() is ignored as a class; its argument is counted. :is() / :where() / :has() take the mo...

Paste CSV, TSV or a JSON array and convert it to JSON, CSV, Markdown table, HTML table or SQL INSERT statements. Handles quoted fields, custom delimiters and header detection. Everything stays in y...

CSS transition-timing-function: cubic-bezier(x1, y1, x2, y2). x is time (0–1), y is progress (can overshoot). Copy the declaration after you like the motion. Respects reduced-motion.

Six words from a 256-word list, picked with crypto.getRandomValues (~48 bits). Not the official 7,776-word EFF list — treat this as a strong memorable password, then store it in a manager. Generate...

Calculate partition sizes, plan disk layouts, convert units, and get the commands to set it all up

Paste a list: drop duplicate lines, sort A→Z or Z→A, trim spaces, ignore case. Stays in this browser — mailing lists and log dumps never leave the device.

Paste an email’s raw headers to inspect the visible From, Reply-To and Return-Path domains, reported SPF/DKIM/DMARC results, and the number of Received hops. Everything is checked in this page; no ...

Open a CSV in Excel and it silently eats leading zeros, turns long IDs into 1.23E+15, makes “1-2” into 2-Jan and gene names like MARCH1 into dates. This finds every cell Excel would mangle and expo...

Tick the stacks you use. Output is a combined .gitignore — copy into the repo root. Git still tracks files you already committed; git rm --cached those separately.

Generate cryptographic hashes instantly. Supports MD5, SHA-1, SHA-256, SHA-384, SHA-512. All processing happens in your browser — nothing is sent to any server.

Strip comments and collapse idle whitespace in HTML or CSS. Not a full parser — keep <pre> and <textarea> out of the input, and do not minify JavaScript here. Local only.

Escape text for safe HTML display, decode named or numeric entities, and inspect the characters in a string. Choose readable entities for the five HTML-sensitive characters or numeric entities for ...

A practical subset: headings, paragraphs, links, images, lists, bold/italic, code, blockquotes, hr. Scripts and styles are dropped. Not a full CommonMark round-trip.

Look up any HTTP status code, filter by class, and copy a one-line explanation. Covers the registered 1xx–5xx codes developers hit in the wild. Entirely offline.

Type any text and watch it get smaller: common letters get short codes, rare ones get long codes, and the result is the exact same idea behind ZIP, PNG and MP3. The tree is the codebook, drawn for ...

Check an International Bank Account Number with the ISO 13616 MOD-97 algorithm, then pretty-print it in groups of four. This confirms the check digits only — it cannot prove an account exists.

Make a .ics file any calendar app can import. Times are written as floating local (no time-zone math). All-day events use DATE values.

32-bit binary32 (float) and 64-bit binary64 (double) bit patterns via typed arrays. Paste a decimal, hex (0x…) or 32/64-bit 0/1 string.

Drop in a photo, logo or screenshot and hover to read any pixel as HEX, RGB and HSL — with a magnifier for precision. The tool also pulls out the image's dominant palette, ready to copy as CSS vari...

Code that won’t compile, a password that “is definitely right”, a search that finds nothing, a spreadsheet match that fails: the culprit is often a character you cannot see. Reveals zero-width spac...

Validate an ISBN-10 or ISBN-13, compute the check digit, and convert between the two. Hyphens and spaces are ignored. Check digits follow the ISBN / EAN rules — this does not look up a book.

Nested objects become dotted keys (user.address.city); arrays use items.0. Unflatten rebuilds the tree. Runs in this page — nothing is uploaded.

Decode and audit JSON Web Tokens offline. Zero network calls — your security tokens never leave your browser.

Press any key to test it live — handy when a laptop key died or a layout is fighting you. Shows event.key, event.code, keyCode, which, modifiers, location, and ready-to-copy event listener code. No...

Searchable reference of 200+ Linux commands — filter by category, copy with one click

Complete reference of Linux signals, process states, and process management commands with examples

Paste log output to get instant analysis, or generate commands to search, filter, and monitor logs

Validate or generate a Luhn (mod 10) check digit. Used by card numbers, IMEI, NPI and some barcodes. This only tests the checksum — it cannot tell you whether a number is issued, active or real.

Make a correctly encoded mailto: link with recipients, cc, bcc, subject and a multi-line body — as a URL, HTML or Markdown — or decode one you found. Runs in your browser.

Interactive spreadsheet grid editor to create, format, and convert tables to GitHub-flavored Markdown, ASCII box art, Unicode borders, HTML, and CSV.

Check everything before the call: see your microphone level move, hear a tone from the left and right speaker, and preview your camera with its real resolution. Audio and video stay inside this tab...

Convert a file extension to a MIME type, or a MIME type back to common extensions. Handy when writing Content-Type headers, nginx maps or <input accept> lists. Lookup is local.

Turn “café”, “don’t” and “привет” back into real text. Reverses UTF-8 misread as Windows-1252 or Latin-1, even when it happened twice or only in parts of the text. Runs in your browser.

URL-safe IDs from crypto.getRandomValues. Default alphabet is A–Za–z0–9_- (64 symbols). Collision odds are about (n²) / (2 × 64^size) for n IDs — this is not a password manager.

Watch a tiny neural network learn XOR — the task that killed the first wave of neural networks, because a straight line can't separate the points. As it trains, the decision boundary curls into a c...

See which trackers and third parties a web page talks to. Load a HAR export from your browser's DevTools, or paste page source, and get a local report. Nothing you load is uploaded.

Draw walls and watch four search algorithms hunt for the goal: DFS wanders, BFS floods evenly, Dijkstra matches BFS on a uniform grid, and A* heads straight for the target. The visited cells and th...

Convert CSS lengths between pixels, rem and em for a chosen root and parent font size. Defaults to the browser 16 px root. Copy-ready declarations, no build step.

Split a URL or a raw ?a=1&b=2 into keys. Duplicate keys become arrays. Build the other way from JSON. Uses the platform URLSearchParams — stays on this device.

The same Fibonacci function, two ways: naive recursion recomputes the same subproblems a staggering number of times, while memoization remembers each answer once. Watch the call tree fill with dupl...

Compare two Semantic Versioning 2.0.0 strings, then bump major, minor, patch or a pre-release. Precedence follows the spec: major.minor.patch, then pre-release identifiers, build metadata ignored.

Convert any text into URL-friendly slugs. Perfect for blog posts, filenames, and SEO-friendly URLs.

Watch six classic sorting algorithms race on the same shuffled data — see exactly why O(n²) sorts crawl while merge and quick sort fly. Every comparison and swap is counted live.

Check the syntax of an SPF or DMARC DNS record you paste, count SPF DNS lookups, or build a new record. Works offline: nothing is looked up or sent.

Shift every HH:MM:SS,mmm timestamp in an .srt by milliseconds (negative to go earlier). Runs in this page — files stay on your device.

Build SSH, SCP, and SSH tunnel commands — fill in the options, copy the command

Subtitles start in sync and slowly slide out of time? That is drift, not an offset — usually a 23.976 vs 25 fps mismatch — and a plain time shift can’t fix it. Give two lines with their correct tim...

Minify and clean SVG markup, remove metadata, editor bloat and unused namespaces, round decimal precision, preview live, and copy optimized SVG.

Generate systemd .service unit files — fill in the details, get a complete service file with install instructions

Paste anything and get it back in every case at once: UPPER, lower, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, aLtErNaTiNg, reversed and URL ...

Encode UTF-8 text as hex or binary, or decode hex/binary back. Spaces in hex are ignored. Binary is 8-bit groups. Nothing is sent anywhere.

Move the stack from peg A to peg C, never putting a bigger disk on a smaller one. The catch: the optimal solution is 2ⁿ − 1 moves, so 8 disks means 255 moves — recursion made visible. Solve it your...

Generate truth tables for logical expressions. Supports AND, OR, NOT, XOR, IMPLIES, and IFF operators.

Convert text to Unicode code points, HTML entities, and escape sequences. Supports all Unicode characters.

Convert Unix epoch timestamps (seconds, milliseconds, microseconds or nanoseconds — auto-detected) to human dates and back. Shows UTC, your local time, ISO 8601, relative time and the weekday. A li...

Percent-encode or decode any text (full encodeURIComponent or URL-safe encodeURI), and break a URL into protocol, host, port, path, hash and an editable table of query parameters. Edit a value and ...

Inspect your browser's user agent string, client hints, screen geometry, GPU WebGL renderer, touch capabilities, color depth, and networking status.

Generate one or hundreds of UUID v4s, time-ordered UUID v7s, ULIDs, NanoIDs, short IDs or custom-pattern codes using the browser's cryptographic random source. Choose case, braces and separators, t...

Build a vCard 3.0 you can save as .vcf and open on a phone. Stays in the browser — no address book is uploaded.

Estimate video file size from duration and video/audio bitrates, or solve for the bitrate that fits a size budget. Formula: size ≈ (video + audio) × time. Container overhead is ignored.

Test color contrast ratios against WCAG 2.2 accessibility standards (AA / AAA) and simulate color-vision deficiencies in real time.

Calculate exact file download and upload durations, test bandwidth capacity for simultaneous 4K streams and video calls, and estimate mobile data cap exhaustion.

Format, minify, validate, and explore XML. Paste messy XML, get clean indented output with syntax highlighting.

Generate high-converting 4-touch B2B cold email sequences. Features real-time spam keyword detection and an inbox deliverability health score. Replaces expensive monthly sales automation subscripti...

Produce real, scanner-readable barcodes — Code 128, Code 39, EAN-13, UPC-A and ITF-14 — and download them as vector SVG or a print-resolution PNG. Barcode generator sites charge a subscription for ...

Design a real logo in the browser and leave with the vector file. Twenty-two hand-drawn icons, five type treatments, four container shapes, gradient or flat colour, and exports as SVG, a 1024px PNG...

Type one or two words that describe what you do and get a few dozen names built from the tricks naming agencies actually use — blends, compounds, prefixes, suffixes, alliteration and invented words...

The one-page strategy board that consultants charge a day rate to facilitate. Fill the nine blocks of a Business Model Canvas or a Lean Canvas, get prompted when a block is too thin to be true, and...

Model startup equity dilution across funding rounds. Calculates Y Combinator post-money SAFEs, valuation caps, employee option pool (ESOP) expansion, and founder equity value without paying thousan...

The offline PandaDoc / HoneyBook killer — build a branded quote, invoice or proposal, add your terms, collect a legally-binding drawn e-signature, and export a print-ready PDF. Payment link, QR, au...

Generate legally-binding Non-Disclosure Agreements (NDA) and Independent Contractor Service Agreements. Customize IP assignment, confidentiality duration, non-solicitation, and jurisdiction with ze...

Paste any contract, terms of service or NDA and get an instant risk map — plain-English summary, red flags, missing protections and a clause-by-clause fix list. Replaces LegalZoom contract review (...

Build a self-hosted cookie banner with real accept / reject / granular choices — the thing Cookiebot, OneTrust and Termly charge a monthly fee for, and the thing most "free" generators only half do...

Preview common CSS keyframe animations, tune duration, delay and easing, then copy a small standalone animation block. The preview honours reduced-motion preferences; use motion as polish, never as...

Shape a card, button or image frame with four independent corner radii, preview the result and copy the compact CSS shorthand. Switch between pixels and percentages, link corners while you explore,...

Tune a CSS box-shadow visually, choose a colour and opacity, test inset mode and copy production-ready CSS. The preview updates as you move the controls, so there is no design account or upload step.

Combine brightness, contrast, saturation, hue, blur and monochrome effects with a live visual preview, then copy one filter declaration. Useful for hero images, hover states and quick image treatme...

Explore real flexbox controls side by side: direction, wrapping, gap and alignment update the preview immediately, then a copyable CSS block records the exact settings. Use it to build nav rows, ce...

Build a responsive CSS Grid visually: set tracks, gap, flow and item alignment, optionally make one card span multiple cells, then copy the CSS. The preview uses real grid properties and runs entir...

Paste a spreadsheet, get a clean dataset. Parses CSV/TSV, detects the delimiter, profiles every column, cleans the rows, and re-exports as JSON, SQL, Markdown, XML or HTML. Nothing is uploaded — th...

Assemble a safe-to-copy cURL command from a URL, method, headers and optional request body. It quotes shell values correctly and never sends the request itself, so you can prepare API calls private...

Write a presentation as plain text and present it from the browser. Split slides with ---, get a live thumbnail rail, speaker notes, a run timer and full-screen mode, then export a single self-cont...

Preview how a subject line and preheader may truncate on mobile or desktop, check length and punctuation, and get practical editing prompts. This is a transparent writing heuristic — not a delivera...

Turn a set of chapters into a real EPUB 3 file your reader can actually open — the job Vellum charges a couple of hundred pounds for and Designrr sells as a subscription. Write in plain text with l...

Make a sharp, lightweight vector favicon from initials or one emoji, tune its colours and shape, then download a ready-to-use SVG. It also gives you the HTML link tag and a data URI — no image uplo...

Draw a real project timeline — tasks, dates, progress, milestones and dependencies — and export it as a clean SVG or a print-resolution PNG. TeamGantt and Microsoft Project charge per user per mont...

Turn a quick list of headers and rows into accessible, escaped HTML table markup with a live preview. Paste pipe- or comma-separated data, add an optional caption, and copy code that works cleanly ...

Batch-shrink photos and screenshots without uploading a single byte. Drop files in, pick a target size and format, and watch the real compressed file size update as you move the quality slider. Exp...

Calculate when to reorder stock using sales velocity, supplier lead time and safety stock. All calculations stay in your browser.

Generate clean, client-ready invoices with zero watermarks. Calculates multi-currency line items, tax, discounts, and payment terms with 1-click browser print to PDF. Instant browser-based invoicin...

Paste any JSON response and get production-ready types in six dialects at once: TypeScript interfaces, a Zod schema, Python dataclasses, Go structs, C# classes and a JSON Schema document. Nested ob...

Build the one-page hub you put in your social bio and download it as a single self-contained HTML file you can host anywhere for free. Linktree charges a monthly fee for themes, analytics and remov...

One-tap background removal, chroma key, edge feathering and 2×/4× upscaling — the offline replacement for remove.bg & Let's Enhance. Flood-fill magic wand, color distance, and canvas compositing. E...

Track real-time company salary burn during meetings. Keep discussions focused, respect employee time, and visualize the true cost of every minute.

Create repeatable sample customer, product or analytics-event datasets as JSON, CSV or SQL inserts. Names and example.test emails are deliberately fictional, so you can prototype safely without upl...

Premium-grade PDF studio that replaces Smallpdf / Adobe Acrobat for everyday jobs — 100% offline, no uploads, no watermarks. Merge, split by pages, compress images → PDF, and extract text. Uses you...

Stamp a logo or a text signature across a whole folder of photos in one pass — tiled, angled and faded so it survives a crop but does not ruin the picture. Desktop watermark apps charge a licence a...

Generate legally-compliant Privacy Policies for websites, mobile apps, SaaS, and e-commerce stores. Includes GDPR, CCPA/CPRA, cookie consent, and third-party processor disclosures without paying re...

Professional audio workstation that replaces Audacity, Adobe Audition & Descript — 100% offline. Record mic, import audio/video, visualize waveform, trim, normalize, fade, adjust gain/speed, and ex...

Professional color system that replaces Coolors, Adobe Color & Stark — 100% offline. Extract palette from any image via k-means, generate harmonies, test WCAG contrast, simulate color blindness, bu...

Professional database studio that replaces Airtable $20/mo, Notion Database & Coda — 100% offline. Spreadsheet grid with types (text, number, select, checkbox, date, formula), filters, sort, views ...

Professional drag-drop design studio that replaces Canva Pro $13/mo, Adobe Express & Figma — 100% offline. Templates for YouTube thumbnail, Instagram post/story, OG image, poster, with layers, text...

Professional document scanner that replaces Adobe Scan, CamScanner & OnlineOCR — 100% offline in browser. Scan images, enhance, crop/rotate, OCR via built-in engine, export PDF/TXT, batch processin...

Professional email builder that replaces BeeFree $30/mo, Mailchimp builder & Stripo — 100% offline. Drag blocks, edit copy, inline CSS, dark mode, mobile/desktop preview, spam score, export HTML. N...

Professional spaced repetition studio that replaces Anki $25 & Quizlet Plus $36/yr — 100% offline. Create decks, import CSV, study with SM-2 algorithm, bury/leech detection, stats, heatmap, export....

Professional form builder that replaces Typeform $25/mo, Tally & Google Forms — 100% offline. Drag-drop fields, validation, logic, themes, collect responses in localStorage, export CSV/JSON, embed ...

Production-grade image studio that replaces TinyPNG, Squoosh & Photoshop batch — 100% offline. Batch compress, resize, convert to WebP/JPEG/PNG, strip EXIF, add watermark, and download. No uploads,...

Production invoicing studio that replaces FreshBooks, HoneyBook & Stripe Invoicing — 100% offline. Create invoices, estimates, recurring subscriptions, track paid/overdue, taxes, discounts, multi-c...

Production-grade JSON studio that replaces Quicktype, JSONPath Online & Postman scratchpad — 100% offline. Format, validate, minify, query with JSONPath, diff, convert to YAML/CSV/XML/TypeScript/Py...

Professional landing page builder that replaces Carrd $19/yr, Webflow $14/mo & Framer — 100% offline. Drag sections (hero, features, pricing, FAQ, CTA), edit copy, themes, responsive preview, expor...

Military-grade password manager that replaces 1Password / Bitwarden for local use — 100% offline, zero-knowledge. Generate high-entropy passwords, check strength, store in AES-GCM vault locked by m...

Professional browser video studio that replaces HandBrake, Kap, EZGIF & Adobe Media Encoder — 100% offline. Trim, compress preview, extract frames, generate thumbnails, GIF preview, mute, rotate, m...

Professional infinite whiteboard that replaces Miro $10/mo, FigJam & Mural — 100% offline. Pan, zoom, sticky notes, freehand drawing, shapes, connectors, text, image upload, layers, export PNG/SVG/...

One place for regular expressions: live match highlighting, a capture-group table, find-and-replace with ready-made text transforms, a plain-English explainer, a searchable cheat sheet, a pattern l...

Paste any resume + job description and get an instant ATS score, keyword gaps, formatting traps and a line-by-line fix list. Replaces JobScan Premium ($50/mo) — 100% offline, no upload, no AI API. ...

Check whether monthly client retainers fit your available hours and reveal effective revenue per hour. All calculations stay in your browser.

Build valid schema.org JSON-LD for the rich results Google actually shows — products with price and availability, FAQs, breadcrumbs, events, local businesses, articles. Fields are validated as you ...

Draft a valid robots.txt and XML sitemap from your own URL list. Add paths or full URLs, set crawl rules and download the result. This is a local generator, not a crawler: it never visits or upload...

The question that ends startups: which month does the bank account hit zero? Enter your cash, your costs and your revenue growth, and it projects 36 months forward, finds your break-even month, cal...

Model recurring revenue lost to churn and the customers needed to maintain or grow monthly revenue. All calculations stay in your browser.

Calculate core SaaS unit economics, Customer Lifetime Value (LTV), Customer Acquisition Cost (CAC), payback period, and cash burn runway. Replaces expensive subscription analytics dashboards.

Record your screen, your webcam, or your webcam as a picture-in-picture over your screen — free, unlimited and watermark-free. Loom puts recording length and viewer counts behind a plan and Screenc...

Encrypt a message or a file with AES-256-GCM using a passphrase only you know, then hand over something that is meaningless without it. Password managers charge a subscription to hold notes like th...

One SEO workspace: audit a page's HTML against more than 35 on-page checks with a score and a fix for each problem, analyse target keywords and readability, preview how the page looks in Google, on...

Build an email signature that survives Gmail, Outlook and Apple Mail, then copy it with formatting intact and paste straight into your mail client. Table-based layout, inline styles only, no script...

Sign with a mouse, a finger or a stylus — the line thickens as you slow down, the way a real pen does — or type your name and get a script version. Save it as a transparent PNG to drop into a docum...

Crop and export pixel-perfect images for every social media network directly in your browser. 100% client-side HTML5 Canvas with zero server uploads, zero watermarks, and zero monthly design subscr...

The two numbers every experiment platform charges you to see: is this difference real, and how long must the test run? Frequentist z-test with confidence intervals, a proper sample-size and duratio...

Make a dense SQL query readable without sending it to a database. This formatter understands common SELECT, INSERT, UPDATE and DELETE clauses, preserves quoted strings/comments, and can output comp...

Write a real set of terms for a small site, shop or SaaS product — the document Termly, iubenda and Shopify's policy apps charge a monthly subscription to generate and re-host. Answer a dozen quest...

Turn customer reviews, tweets, and testimonials into high-converting social proof cards. Generates pure zero-dependency HTML & CSS code with zero third-party tracking scripts that hurt Google PageS...

Compare two versions of text and see additions, removals and unchanged passages in a clean unified diff. Choose line-by-line for documents and code, or word-by-word for short edits. Everything is c...

Run a stopwatch on real work, round it the way your contracts do, and turn the week into a CSV or a printable invoice-ready timesheet. Toggl, Harvest and Hubstaff charge per seat per month and hold...

Offline transcription workspace that replaces Otter.ai / Descript — upload audio/video, auto-transcribe with Web Speech API where available, hand-correct on a waveform, and export SRT / VTT / TXT. ...

Generate standardized Google Analytics 4 (GA4) tracking URLs across multiple marketing channels simultaneously. Enforces lowercase slugification, auto-encodes illegal spaces, and exports batch CSVs...

Cold water kills strong swimmers in minutes, and it kills them long before hypothermia is even possible. Most people who die in UK waters were never trying to swim far — they fell in, gasped, and i...

Almost every driving emergency has one instinctive response that makes it worse and one trained response that fixes it. Pick the situation. You get the correct order of actions, the specific thing ...

Choose what you have actually observed to get a civilian-safe next-step checklist. This guide cannot identify a drone, its operator or intent—and a sighting alone is not evidence of a threat or an ...

In every major incident the mobile network is the first thing to fail — not from damage, but from everybody calling at once. This works out what you can actually reach with, how far a handheld radi...

Three different emergencies need three different bags, and most people prepare the wrong one. Build all three here, weigh them against what you can actually carry, and print a checklist. The point ...

Most fire deaths are not from flames — they are from smoke, at night, in homes where nobody had ever worked out a route. Answer twenty questions about your home and this builds a real escape plan, ...

Three things people get wrong in the first two minutes, and all three can be fatal: what to touch when you smell gas, how to recognise carbon monoxide poisoning before someone collapses, and what a...

Temperature alone lies. Wind takes heat off you far faster than the number suggests, humidity stops you cooling yourself down, and wet clothing changes everything again. This works out what the air...

Every knot you actually need, with a diagram, step-by-step tying instructions, what it is for, how much rope strength it costs you and whether it jams solid afterwards. Filter by job, search by nam...

Most personal-safety advice is about what to do when something is already going wrong. The useful part is earlier: noticing a situation while it is still a choice. Score a journey you are about to ...

The first ninety seconds after a poisoning are mostly about not making it worse, and most of the folk advice is actively dangerous. Find the substance, pick how it got in, and get the specific firs...

You can live weeks without food and about three days without water. This works out how much to store, how many containers that is, and — the part people get wrong — exactly how to make a questionab...

Power, water, phone service, payments and transport can fail separately—or at the same time. Choose a few to rehearse and get a short household action list. The cause does not need to be known: thi...

Dial in high-tech planted tank CO₂ injection. Calculate dissolved CO₂ concentration (ppm) from pH/KH equilibrium, simulate 4 dKH drop checker reagent colors, and estimate cylinder gas lifespan.

Calculate precision heating wattage, evaporative surface loss, and cooling chiller ratings. Eliminates the catastrophic "stuck heater" disaster using fail-safe dual heater redundancy math.

Calculate photosynthetically active radiation (PAR) penetration at substrate depth, daily light integral (DLI), and generate split photoperiod schedules to suppress nuisance algae.

Plan your planted tank and hardscape layout. Calculate exact substrate volume, sloped perspective depth, commercial bag counts (3L/9L aqua soil, 20lb/50lb sand), and stone weight for Iwagumi and Ry...

Calculate gross and true net water volume, accounting for glass thickness, top water margin, substrate, and hardscape displacement. Computes total filled weight and structural floor joist loading.

Generate weekly nutrition schedules with gut-clearing fast days. Calculate safe vacation fasting limits, prevent the catastrophic "neighbor overfeeding" disaster, and generate foolproof pet-sitter ...

Identify fish ailments by symptom and calculate precision medication dosages based on true net water volume. Includes invertebrate toxicity warnings and scaleless fish safety flags.

Build your community aquarium roster. Calculates true metabolic bioload, swimming strata distribution (top, mid, bottom), temperature and pH overlap, and flags aggression and schooling warnings.

Master the nitrogen cycle without harming livestock. Calculate exact pure ammonia dosing, simulate bacterial colonisation curves (Nitrosomonas & Nitrospira), and validate your 24-hour clearance test.

Precision aquatic water chemistry toolkit. Calculate exact nitrate dilution percentages, RO/DI remineralization buffers for dwarf shrimp and plants, and marine saltwater salt batch mixing.

Calculate the exact time required to binge any anime series. Account for OP/ED skipping, filler elimination, playback speeds ($1.0\times - 2.0\times$), and view your estimated completion date.

Explore the psychological Dere spectrum of anime character archetypes. Inspect behavioral triggers, iconic representatives, and take the 4-question archetype diagnostic quiz.

Plan your anime convention expedition (Anime Expo, Otakon, Anime NYC, MCM). Split hotel costs across roommates, budget Artist Alley prints and scale figures, and enforce the golden 5-2-1 survival r...

Distinguish manga canon, anime canon, and skippable studio filler arcs across major long-running anime. Search any episode number or generate a streamlined, filler-free binge list.

Find the perfect anime tailored to your exact emotional state and available time. Filter by desired mood (cathartic tears, adrenaline hype, psychological mind-games, or cozy healing), episode lengt...

Analyze the rhythmic energy of iconic Anime Openings and Endings. Explore the legendary Japanese TV 89-second broadcast rule, tap along with the real-time BPM tapper, and audition metronome tempos.

Decode iconic anime verbal tics (*dattebayo*, *de gozaru*, *nya*), battle cries (*omae wa mou shindeiru*), and dialogue tropes with native Japanese audio pronunciation.

Convert Tokyo Japan Standard Time (JST / UTC+9) anime broadcasts to your local timezone. Decodes Japanese TV late-night 30-hour clock conventions (e.g. 25:30 JST = 1:30 AM next day) and calculates ...

Scale anime weapons and props proportionally to your exact real-world body height. Calculate blade length, hilt dimensions, EVA foam sheet requirements, and convention-legal weight estimates.

Finished an anime season and want to continue the story? Find the exact manga chapter and volume where the anime left off, along with chapter pacing and estimated reading catch-up time.

WORLD'S FIRST interactive DE solver with step-by-step explanations, visual graphs, and real-world applications. Used by universities worldwide!

The kettle costs pennies and the tumble dryer costs a fortune — build your house as a list, see what each appliance really costs per day, month and year, and find the ones worth changing first.

APY = (1 + APR/n)n − 1, where n is compounds per year. APR is the quoted nominal rate; APY (EAR in the UK) is what you actually earn or pay after compounding. Savings ads in Britain must show AER.

Generate formal dispute letters for unauthorized charges, unfair fees, and billing errors — ready to send to your bank

Track your complaint deadlines — never miss a bank's response window, FOS deadline, or court limitation period

Compare bank switching bonuses, calculate total savings, and see how much your loyalty is costing you

See how scheduled income and bills affect a running balance over the next 30, 60 or 90 days. Add one-off or repeating entries, spot a projected below-zero day, and export the forecast. No bank conn...

Find the sales volume needed to break even and calculate required revenue. For educational and planning purposes only.

Count weekdays between two dates, or add N working days to a start date. Weekends are skipped; paste extra holidays if you need them. All counting stays on this device.

CAGR = (end ÷ start)1/years − 1. The smoothed yearly rate that takes a starting value to an ending value. It ignores deposits, fees and the bumpy path in between — a sketch, not a forecast.

Work out the true cost of running a car in the UK — depreciation, fuel or electricity, insurance, VED road tax, servicing, MOT, tyres and repairs — per month and per mile. Everything calculates loc...

Plan, track, and optimize your Christmas gift spending. Avoid overspending with smart budgeting! ✅ Features: Gift ideas, price tracking, comparison shopping, receipt scanning

Explore which combination of community projects fits a shared budget. Use member-agreed support scores to compare the best affordable bundle with the projects it leaves out.

Calculate future value, growth projections, and compare investment scenarios. Visualize wealth accumulation over time with detailed breakdowns. ✅ Features: Regular contributions, inflation adjustme...

Make a cooperative’s surplus distribution understandable to every member. Set an agreed reserve share, then compare equal-member, contribution-weighted and blended allocations that add up exactly.

Bands come from your home’s value on a fixed historic date — 1991 in England and Scotland, 2003 in Wales. Find your band, estimate the real bill from your council’s Band D figure, and see what the ...

Challenge incorrect entries on your credit report — generate dispute letters for credit agencies and banks

Convert between 20 major currencies using built-in offline reference rates. No sign-up, no network — works fully offline. Rates are indicative (refreshed Sep 2026); check your provider for live quo...

Calculate date differences, add/subtract days, and discover interesting date facts instantly.

Calculate how long one balance takes to clear — and what extra payments save in interest. Estimates only, not financial advice. If debt feels unmanageable, speak to a free debt adviser.

Calculate final prices after discounts and taxes. Compare multiple deals and save your calculations.

Trailing yield = annual dividends per share ÷ price. Forward yield uses the next expected year. Cover = EPS ÷ DPS. This is a ratio, not investment advice, and ignores tax wrappers.

Estimate the fully loaded annual and monthly cost of hiring beyond the headline salary. All calculations stay in your browser.

Suppliers advertise the unit rate because it is the flattering number, but the standing charge is paid every single day whether you use anything or not. This compares the real annual cost — and, mo...

Estimate kWh, cost and wall-clock time to charge an electric car. Uses usable battery size, start/end state of charge, charger kW and unit rate. Peak DC rates taper — treat rapid times as optimistic.

Smart budgeting with predictive analytics, financial health scoring, and personalized optimization strategies.

Build a complete FOS complaint — step by step. Get your money back when the bank refuses to help

Estimate your Financial Independence number, years until retirement, and compound investment growth trajectory using the 4% Safe Withdrawal Rule. Illustrative projections, not financial advice.

Calendar quarters, the UK tax year (6 April–5 April) and the US federal fiscal year (starts 1 October). Pick a date; see which Q you are in and when it ends.

Delayed, cancelled or denied boarding? UK261 can entitle you to up to £520 per passenger — and claim firms take 25–40% of it for filling in a form. Check your entitlement and generate the airline l...

Stop undercharging. Calculate your true sustainable hourly and day rates by factoring in unbillable admin time, self-employment taxes, equipment expenses, pension, and paid time off.

Calculate trip fuel costs, compare vehicles, track carbon footprint, and find optimal routes. Real-time calculations with environmental impact!

Gift Aid is the rare tax relief where everybody wins: the charity gets 25p more for every pound you give, at no cost to you, and if you pay tax above the basic rate you can claim some of it back pe...

Track your grocery spending, categorize items, and stay within your budget with smart insights.

Falling behind on rent, energy or debts? Silence makes everything worse. Build a calm, formal hardship letter with a budget summary that asks for a payment plan, freeze or reduction — in UK, US or ...

Calculate the TRUE cost of your bank account — overdraft fees, ATM charges, FX markups, and hidden costs that banks hope you won't notice

Tax-free Approved Mileage Allowance Payments for 2026/27: cars and vans 55p for the first 10,000 business miles then 25p; motorcycles 24p; bicycles 20p; plus 5p per passenger per mile. Rates from G...

Work out statutory UK holiday for part-timers, mid-year starters and leavers, and irregular-hours staff — including the 12.07% accrual method. Employers get this wrong constantly. Nothing you enter...

Enter your hourly rate and hours (including overtime at 1.5× or 2×, night or weekend premiums) to see weekly, monthly and annual gross pay, an approximate UK take-home after Income Tax, National In...

Convert an hourly rate to a yearly salary (and back) using your hours per week and weeks per year. Defaults match a UK full-time week. Gross pay only — tax is not deducted.

Calculate real-world purchasing power with historical data, multiple currencies, and personalized financial scenarios.

Watch your money multiply: Calculate how small investments today can grow into significant wealth over time through compounding. Illustrative estimates only — not financial advice; markets can fall...

Calculate statutory or agreed late-payment interest and a clear updated invoice total. All calculations stay in your browser.

Compare take-home pay as a contractor: inside IR35 through an umbrella company versus outside IR35 through your own limited company. Editable tax rates, full working shown, nothing leaves your devi...

Put up to three roles side by side: base pay, expected bonus, employer pension, your estimate of other benefits, commuting costs and time, contracted hours, and paid leave. No offer is ranked for you.

Unpaid invoice? UK law lets you charge 8% above the Bank of England base rate plus fixed compensation on overdue business invoices — automatically, even if your contract never mentioned it. Calcula...

Compare the true cost of leasing a vehicle against buying it outright or on finance, over the same term. Accounts for deposit, monthly payments, residual value and what the car is worth at the end.

Lenz's law electromagnetic braking exhibit. Drop a strong neodymium magnet down metal tubes; circulating eddy currents oppose motion, creating levitation-like terminal float.

Calculate monthly loan payments, view complete annual and monthly amortization schedules, and simulate the interest savings of extra principal payments.

Find practical opportunities for local enterprises using a community’s own spending sample. Group purchases by category, compare local and outside supply, and test an editable local-capture scenario.

Loan-to-value = mortgage ÷ property price. UK product tiers often sit at 60, 75, 85, 90, 95%. Deposit is price − loan. Not a lender decision and not advice.

Work out the change from UK coins and notes, then hand the exact coins with the fewest pieces. Learn the greedy method for 1p–£2 and practise 5 rounds. Everything runs on your device.

Convert cost, selling price, markup and profit margin. Markup is profit ÷ cost; margin is profit ÷ selling price. Mix them up and you under-price. Nothing is stored.

Track your spending, set a budget, and see where your money goes — simple enough for your first budget

Lenders look at two things at once: an income multiple and an affordability stress test at a rate higher than you will actually pay. This works out which of the two bites first for your numbers, th...

Calculate detailed mortgage payments with amortization schedules, extra payments analysis, and regional comparisons. 💰 Monthly payments • Total interest • Payoff time • Amortization schedule • Reg...

See how overpaying cuts your mortgage term and total interest. Add a monthly overpayment, a lump sum, or both, and compare against paying the normal schedule. Full amortisation worked out on your d...

A local, walker-style evolutionary search for copy-signal filters, with a built-in primer on reading gold (XAU/USD) and pairs such as EUR/USD. Import a chronological trade CSV; candidate genomes co...

Add weeks or months to the day you hand in notice. UK statutory minimums are 1 week after a month’s service and 1 week per year after two years (capped at 12) — contracts are often longer. This is ...

Spell out a number in British or American English, including the cheque / check form with fractional currency. Handles values from 0 to 999,999,999,999.99. Nothing is sent off this device.

Calculate how much you've been overcharged on overdraft interest and fees — then generate a reclaim letter

Broke before payday? Enter what you have left and what is due, and get a day-by-day survival budget that protects rent, heat and food first — and tells you honestly which bills can be paused or neg...

Complete personal finance dashboard: Track net worth, analyze assets vs liabilities, set financial goals, project future growth, and monitor your journey to financial freedom.

Networks hide the handset price inside the monthly figure. Put the two deals side by side, apply the annual April price rise, and see the real total — then haggle or walk.

More than one prescription a month? An NHS prepayment certificate caps the cost — but only past the break-even point. Enter your items and see whether paying per item, 3-month or 12-month PPC wins.

Scale a full-time equivalent salary to part-time hours, or the other way. Uses working hours only — not tax, NI, or pension. UK job ads often quote FTE then “pro rata”.

Quote client projects from real labour, expenses and contingency while protecting a target profit margin. All calculations stay in your browser.

Delay Repay pays you for arriving late — but the clock runs on your arrival at your final destination, not on the departure board, and single, return and season tickets are compensated on three dif...

Work out your UK statutory redundancy pay, notice period, accrued holiday and how much of a settlement is tax-free — with the full age-banded breakdown, year by year. Nothing you enter leaves your ...

Split rent among roommates, calculate per-person costs, and account for room size differences. Supports multiple currencies and custom splits.

Compare the 5-year cost of renting vs buying the same home. Includes mortgage interest, deposit opportunity cost, buying costs, and equity built. Estimates only — not financial advice.

Compare gross yield, net yield and monthly cash flow for a prospective rental property. All calculations stay in your browser.

Split a restaurant bill fairly: add each dish and tick who shared it, set a service charge or tip, and get an exact per-person total including their proportional share of tax and tip. Handles "I on...

Estimate your retirement savings growth with compound interest. ⚠️ Educational only — consult a financial advisor.

Work out what survey and get-paid-to sites are actually worth per hour before you give them your evenings. Uses realistic rate bands rather than the “earn &pound;500 a month from your sofa” numbers...

Calculate Return on Investment with advanced metrics and comparisons. Supports annualized returns and multiple currencies.

Years to double ≈ 72 ÷ annual %. At 6% that’s about 12 years; at 9% about 8. The exact figure is ln(2)/ln(1+r). A back-of-envelope for interest, inflation and population — not a guarantee.

Calculate net salary after taxes, deductions, and contributions. ⚠️ Estimates only — consult a tax professional.

Commission from a sale amount and rate, with an optional second-tier rate above a threshold (common in sales plans). Gross figures — tax is not deducted.

Calculate how much your savings will grow with regular deposits and compound interest.

Goal + deadline + starting pot → the exact monthly amount. Or tell it what you can afford each month → your finish date. Includes a 3–6 month essential-expenses emergency-fund check and a progress ...

Check if your credit card purchase is protected under Section 75 — calculate your claim and generate the letter

Calculate court costs, check eligibility, and generate your claim — the nuclear option when banks refuse to play fair

Build a proper Letter Before Action for an unpaid debt — with statutory interest calculated to the day, a claim-fee estimate and a 14-day deadline. Then copy it into your email or post. Free, local...

💸 Plan your finances: Calculate mortgage, car, personal and student loan payments with amortization schedule. Compare scenarios and save thousands!

Test a member-funded support pot before making promises. Model regular contributions, agreed grants and running costs, add a one-off disruption, and see when the fund crosses its reserve floor.

Reverse a published percentage + pence fee so you know what you keep, or what to charge to net a target. Default rates are the common UK consumer-card / PayPal numbers — your contract may differ.

Force your bank to reveal ALL data they hold on you — internal notes, decision records, credit scoring, and communications

Track your subscriptions, manage renewals, and optimize spending

Estimate income tax, national insurance, student loan repayments, and take-home pay for UK taxpayers — by week, fortnight, month, quarter or year. Based on 2026/27 UK tax bands.

Check your deposit against the statutory cap, see when it must be protected and returned, and understand the remedies if the landlord gets it wrong. England rules; ask for full compliance history b...

Calculate tips, split bills, and see exactly how much everyone owes. Supports multiple currencies!

Add A-level, AS and T Level grades to a running UCAS tariff total. Offers are often “BBB (120)” — this is the current A-level band (A* = 56). Always check the course page; some universities ignore ...

Funded hours, Tax-Free Childcare and Universal Credit childcare stack in ways nobody explains at the nursery door — and the difference between them is often more than a car payment. Put in what you...

A council Penalty Charge Notice and a private Parking Charge Notice look identical on the windscreen and obey completely different rules: different deadlines, different appeal bodies, different con...

Estimate SDLT on residential purchases in England & Northern Ireland using HMRC bands. Covers standard, first-time buyer relief and additional-property surcharge. Estimates only — not tax advice; c...

Shops price things so you cannot compare them: 340 g here, 12 × 30 g there, "3 for £5" on the shelf edge. Put in what is actually on the shelf and this reduces everything to one number. Handles mul...

Add tax to a net price or extract tax from a gross (inc-VAT) figure. Presets cover UK VAT, common EU GST/VAT rates and US-style sales tax. Arithmetic only — not tax advice.

Compare real-time decentralized transaction fees, DEX swap overhead, and smart contract execution costs across Solana, Base, Ethereum L1, and Polygon.

Set the total you are actually willing to spend, choose your guest count, and get a per-category breakdown with sensible starting percentages you can push around. The cost-per-guest number keeps ev...

Set retail and wholesale prices while seeing your margin and the retailer’s margin side by side. All calculations stay in your browser.

No money to start a business? Start anyway. Tell it your skills, time and tools and it matches you with micro-businesses you can launch for almost nothing — with pricing maths, a 7-day launch plan ...

Acoustic resonance installation. Granular silica particles migrate across a vibrating resonant Chladni plate into standing wave geometric nodal lines.

International acre is exactly 4,046.8564224 m²; a hectare is 10,000 m² (a 100 m square). UK land ads mix acres and hectares. Edit any field.

Body Mass Index

Find the exact point on the far side of the planet from anywhere, then drill a straight frictionless tunnel to any second place and drop a capsule down it. The fall time is integrated through the r...

Calculate pixel dimensions while locking exact aspect ratios (16:9 widescreen, 9:16 vertical TikTok/Shorts, 4:3 classic, 1:1 square, 21:9 cinema). Generates modern CSS `aspect-ratio` code snippets.

Planets move in elliptical orbits with the Sun at one focus.

Kristian Birkeland's Terrella experiment. Solar wind plasma streams channeled along geomagnetic dipole field lines excite shimmering atmospheric auroral ovals.

Tyre, compressor and scuba pressures. 1 bar = 100 kPa = 14.5038 psi. Standard atmosphere is 101.325 kPa (14.696 psi). Gauge vs absolute is your problem — this is a unit convert only.

Hours ≈ (capacity mAh × (voltage / load voltage) × efficiency) / load mA. A 2000 mAh cell at 100 mA is about 20 hours at 100% — real packs are less because of cut-off voltage and converter loss.

Accounts for battery aging, temperature, and discharge limits

Compute natural flexural vibration eigenfrequencies and mode shapes for structural beams ($EI \frac{\partial^4 w}{\partial x^4} + \rho A \frac{\partial^2 w}{\partial t^2} = 0$). Inspect nodal point...

Convert wind speed to a Beaufort force (0–12) using the Met Office mean-speed bands. Force is a class, not a precision instrument. Gusts can sit a force higher than the mean.

Calculate and explore basic biology values. Choose a tool, enter values, and get results with formulas. Educational tool for understanding biological calculations.

Bioluminescence is the miracle of "cold light"—producing near 100% luminous efficiency with zero thermal waste. Discover how enzyme Luciferase oxidizes substrate Luciferin using cellular ATP, agita...

Look up boiling points of common substances at 1 atm. Converts between Celsius, Fahrenheit, and Kelvin. Values are at standard pressure (1 atm). Actual boiling points may vary with altitude and pur...

In 1696, Johann Bernoulli challenged the world to find the path of fastest descent between two points under gravity. The answer is not a straight line—it is a cycloid! Test the race in real-time an...

Estimate breaker size for a circuit. Always verify with a qualified electrician and local electrical codes. ⚠️ Educational only — not for actual electrical installations.

Instant, free online Cable Length & Voltage Drop tool. No signup required.

Calculate capacitor values, RC time constants, impedance, and filter characteristics. ⚠️ Educational only — verify with datasheets and professional standards.

°F = °C × 9/5 + 32. Kelvin = °C + 273.15. Absolute zero is 0 K (−273.15 °C). Edit any box — weather, ovens and science labs all use different scales.

Nonlinear chaos theory exhibit. A metallic pendulum swings over three magnetic attractors, demonstrating sensitive dependence on initial conditions.

Explore Ernst Chladni's 1787 acoustic nodal resonance figures. Observe sand grains scatter away from high-amplitude vibrating antinodes and crystallize into intricate geometric standing wave geomet...

Calculate circuit load, breaker size, and wire sizing. Perfect for DIY projects and planning.

A falling climber does not load the system with their body weight — they load it with several times that, and the top runner takes more than the climber does. This works out impact force from the f...

Aerodynamic levitation exhibit. High-velocity air jet traps a floating sphere via Bernoulli low-pressure depression and Coandă wall adhesion even when tilted.

Generate algorithmic color harmonies (Complementary, Triadic, Analogous, Split) and verify accessibility with real-time WCAG 2.1 AA/AAA contrast ratio verification.

Learn the 16-point compass rose: convert between named bearings and degrees, then practise reading them on a marked compass — forward and back bearings, with instant feedback. Runs in your browser,...

Calculate conduit sizes based on NEC requirements, wire types, and installation conditions. ⚠️ Disclaimer: For educational purposes. Always consult NEC codebook and licensed electrician.

One position, every notation: GPS decimal degrees, degrees-minutes-seconds, marine DDM, UTM, MGRS, the British Ordnance Survey grid, geohash, Plus Code and the Maidenhead locator used by radio amat...

Compare countries by population, area, GDP, and more — with animated bar charts and data cards

Simulate multi-degree-of-freedom coupled mechanical oscillators. Observe symmetric ($\omega_1$) vs anti-symmetric ($\omega_2$) normal modes and cyclic mechanical energy sloshing ($T_{beat}$).

Build simple cubic, BCC, FCC, diamond, rock-salt, CsCl and HCP crystals in 3D, slice them with any Miller plane (hkl), and calculate theoretical density, packing fraction, coordination number, d-sp...

Analyze classical mass-spring-damper dynamics ($m\ddot{x} + c\dot{x} + kx = F_0\cos\omega t$). Inspect damping ratios ($\zeta$), Q-factor resonance peaks, phase lag, and transient vs steady-state r...

We live in 3 spatial dimensions — but why 3? Explore what life would be like in 1D, 2D, 4D, and beyond. Each dimension changes the laws of physics.

Type any DNA sequence and watch it become a spinning double helix — with correct A‑T / G‑C pairing, hydrogen bonds, live GC content, mRNA transcription and protein translation. Includes a mutation ...

Paste a DNA or mRNA sequence and watch it get transcribed and translated into amino acids — with a visual codon table

Simulate frequency shifts and wavefront compression for acoustic sound waves and relativistic light redshift ($z$). Features real-time wavefront propagation canvas and Web Audio tone simulation.

Simulate non-linear Hamiltonian chaos via Lagrangian mechanics solved with 4th-Order Runge-Kutta (RK4). Track sensitive dependence on initial conditions (Butterfly Effect) with an overlaid $0.001$ ...

Size earthing conductors for fault protection. For qualified electricians — always verify with local regulations.

Move past vague carbon guilt. PlanetPositive pinpoints the exact 80/20 high-leverage lifestyle actions that slash personal emissions the fastest while saving hundreds of pounds each year.

Albert Einstein derived special relativity with an astonishingly simple thought experiment: a "light clock" bouncing a photon between two mirrors. Because the speed of light $c$ is constant for all...

Place point charges in 3D space and watch Coulomb field lines trace themselves from + to −. Includes a potential heat-map plane, a movable probe that gives the exact field E, potential V and force ...

🔬 A comprehensive electrical engineering toolkit for professionals and students. Includes circuit analysis, power calculations, and energy conversions with real-world context.

🔧 Professional-grade calculations: Calculate electrical loads for homes, offices, or circuits. Includes NEC compliance tips and safety warnings.

Global electrical standards reference (IEC, NEC, BS): wiring, protection and installation rules. For qualified electricians and engineers.

Watch light travel as perpendicular E and B fields in 3D. Dial in linear, circular or elliptical polarization, send it through a polarizer to verify Malus's law, and convert between wavelength, fre...

Watch Conway's Game of Life: 4 simple rules create self-replicating patterns, computation, and open-ended complexity from nothing.

Calculate electricity costs, carbon footprint, and savings potential for any appliance. Track your energy usage and find ways to save money!

Why does time only flow forward? Watch entropy increase in real-time as ordered systems dissolve into disorder — the fundamental law that gives time its direction.

Calculate environmental impacts, explore sustainability metrics, and learn fascinating facts about Earth's systems. Make informed decisions for a greener planet!

Watch AI creatures evolve to walk, survive disasters, find food, and adapt! 10 terrain types, random events, food chains, achievements, and deep genetics. Creatures improve through natural selection.

Four things photographers work out in their heads and get wrong under pressure: what shutter speed balances a change of aperture, how long an ND filter needs, how much of the frame is actually shar...

Simulate Michael Faraday's 1831 parametric liquid surface waves ($\omega^2 = [gk + \frac{\sigma}{\rho}k^3]\tanh kh$). Observe subharmonic resonance ($f_{wave} = f_0/2$) and pattern transitions acro...

Convert height between feet+inches, centimetres and metres. Uses the international inch (exactly 25.4 mm). Edit any box — the others update.

Rosensweig normal-field magnetic instability simulator. Superparamagnetic liquid self-organizes into conical spikes balancing surface tension and magnetic stress.

Total internal reflection fiber optics lab. Explore critical angle guidance, acceptance cone numerical aperture (NA), and macro-bending radiation loss.

Yoshiki Kuramoto's nonlinear synchronization model. Independent bioluminescent fireflies spontaneously phase-lock into simultaneous collective pulsing.

Learn 40 countries with flip flashcards, then test yourself on capitals and flags. Streaks, scoring and fun facts make world geography stick.

A chimney is an engine: hot gas inside, cold air outside, and the density difference pulls the fire along. This works out how much draught your flue actually generates, how fast the gas moves, how ...

Aerodynamic wind tunnel museum exhibit. Visualize laminar airflow, von Kármán vortex shedding, and lift/drag forces around aerodynamic obstacles.

Léon Foucault's 1851 Paris Panthéon experiment proving Earth's diurnal rotation. The swing plane stays fixed in inertial space while Earth rotates below.

Synthesize planar four-bar kinematic mechanisms. Classify via Grashof's Theorem ($s + l \le p + q$), trace coupler curves (Chebyshev, Watt, Hoeken), and analyze transmission angles.

Gravitational N-body astrophysical simulation. Watch two disk galaxies collide as differential tidal forces eject long parabolic stellar bridges and tails.

UK pint is 568 ml; US pint is 473 ml. UK gallon is 4.54609 L; US gallon is 3.78541 L. Edit any box — the others follow using the same liquid volume. Cooking cups are a different mess.

Explore genetics through interactive simulations, DNA analysis tools, and educational content. Perfect for students and enthusiasts!

Type or click out a boundary and get its true area on the curved Earth using the spherical-excess formula — the same maths GIS packages use — alongside the flat-map answer so you can see exactly ho...

Add countries, capitals, and notes to build your geography study list.

Explore geology concepts and discover fascinating facts about Earth's structure and processes.

General Relativity astrophysics exhibit. Drag a supermassive Schwarzschild black hole across cosmic starfields to observe Einstein rings and photon deflection.

Why does a London–Tokyo flight arc over Siberia? Compute the true shortest path between any two points — Vincenty distance on the real ellipsoid, initial and final bearings, waypoints along the way...

Sunlight arrives easily, but the infrared Earth re-radiates gets intercepted by greenhouse gases. Watch photons battle through the atmosphere and see why the surface must warm until the books balance.

Explore rigid body rotational mechanics ($\boldsymbol{\tau} = \boldsymbol{\Omega}_p \times \mathbf{L}$). Calculate steady precession velocity ($\Omega_p = \frac{mgr}{I_z \omega_s}$), nutation frequ...

NWS Rothfusz heat index from shade air temperature and relative humidity. Officially for ≥ 27 °C. Full sun can feel several degrees worse. Not medical advice — heatstroke is an emergency.

Built on Naismith's Rule, the estimate mountain rescue has used for a century: allow an hour for every 5 km, plus a minute for every 10 m climbed. Then it adds the two things that actually decide w...

Create beautiful visual timelines — add events, see them plotted chronologically with color-coded categories

Optical spectrometer bench. High-density holographic diffraction grating disperses atomic gas emission into discrete quantum spectral fingerprints.

How far can you actually see, and how much of that distant hill, ship or radio mast is hidden behind the bulge of the Earth? Enter two heights and a distance and get the geometric answer, the refra...

Convert mechanical horsepower, metric PS and kilowatts, and compute power from torque × RPM. 1 hp = 745.7 W; 1 PS = 735.5 W. Power (kW) = torque (N·m) × RPM / 9549.

A real ray trace: sunlight enters a raindrop, bends (refracts), bounces once (or twice) off the back, and comes back at ~42° — split into colours because each wavelength bends a different amount.

Interactive body systems — click organs and systems to learn their functions, facts, and connections

See the real quantum wavefunctions of hydrogen as glowing 3D probability clouds sampled from |ψ|², coloured by phase. Pick n, l and m, slice the cloud to reveal nodes, and calculate the energy, mea...

Professional inductance calculator with real-time visualization, multiple coil types, and comprehensive electrical analysis.

Explore all 118 elements — search by name, symbol or number, then click any element for detailed properties, electron configuration, discovery history and curator notes

Atmospheric fluid shear-flow instability. Two fluid layers with differing densities and velocities roll up into breaking ocean-billow cloud vortices.

Conservation of momentum and kinetic energy exhibit. Demonstrates compressive acoustic stress wave transmission across elastic collision chains.

10 safe, spectacular experiments using stuff already in your kitchen — each with step-by-step instructions, the real science explained, and safety notes. Perfect for curious kids and parents.

One knot is one nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 kn = 1.852 km/h ≈ 1.15078 mph. Used by ships, aircraft and marine forecasts.

Type in twelve monthly temperatures and rainfall totals and this runs the full Köppen–Geiger decision tree on them — the same classification used on every climate map — showing not just the code (C...

Plan lab experiments by organizing materials, steps, and timing. Enter details and generate a structured plan.

Review lab safety rules and generate reminders for safe scientific work.

R = (supply − LED Vf) / current. Typical Vf: red ~1.8–2.2 V, green/blue/white ~3.0–3.4 V. Always put a resistor in series with a bare LED on a voltage source — the LED will not self-limit.

Rough incandescent, halogen and CFL wattage versus LED lumens. Packaging lumens win over “60 W equivalent” marketing. Efficacy defaults to typical household LEDs (~90 lm/W).

Professional lighting design calculator with comprehensive room analysis, fixture selection, and energy efficiency recommendations. ⚠️ Educational tool — consult certified lighting designers for ac...

Follow a flash from charge separation to thunder: colliding ice makes charge, a stepped leader feels its way down, a streamer connects, and a 30,000 A return stroke heats the air hotter than the Su...

Dual-galvanometer laser projector simulating orthogonal harmonic oscillations, phase shifts, and phosphorescent persistence curves.

Simulate fundamental boolean logic gates (AND, OR, XOR, NAND) and digital circuits with live voltage probes and dynamic truth tables.

Fire an electron, proton or ion into electric and magnetic fields and watch F = q(E + v × B) carve glowing 3D paths — cyclotron circles, helices, E×B drift and magnetic-mirror style spirals. Get th...

Lux = lumens ÷ area (m²) when light is spread evenly. A 800 lm bulb over a 10 m² desk is 80 lux — offices often want 300–500 lux. Beam angle and bounce are ignored.

Calculate material properties and explore fascinating facts about metals, polymers, and composites. Uses real material properties from established databases.

Convert length, area, mass, and temperature without hunting for formulas.

Explore melting points of hundreds of substances. Compare materials, convert units, and learn about phase changes.

In standard materials, the refractive index is always positive ($n > 0$). But engineered metamaterials achieve negative permittivity ($\epsilon < 0$) and permeability ($\mu < 0$), reversing Snell's...

Calculate essential microbiology values and explore fascinating facts about the invisible world of microbes. 🧫 Growth rates • Dilutions • Microbial facts • Educational insights

Kinetic optical interference exhibit. Overlay geometric optical gratings and rotate them to observe emergent macro-scale moiré superlattices.

Eleven molecules and crystals as true ball-and-stick 3D — from water to a salt lattice to a diamond unit cell. Bonds are detected automatically from atomic distances, double/triple bonds included. ...

The site's own map, right here in the card. Drop two points — a town name, a coordinate pair, a Plus Code, a UK grid reference, a UTM coordinate, a Maidenhead locator or a geohash — and get the geo...

Calculate motor running/starting currents, cable sizing, protection devices, and voltage drop analysis for electrical installations. 🔧 Running current • Starting current • Cable sizing • Protectio...

Learn to spot 24 common UK/European plants and fungi from the features that actually matter in the field — leaf shape, flower colour, stem, habitat, season and a safety-relevant lookalike. Three mo...

Water in a swell doesn't travel — each parcel runs in a circle while the wave shape races on. Watch the orbit shrink with depth, then shallow the water until orbits squash and the wave breaks.

Instant voltage, current, resistance, and power calculations.

Arthur Ashkin's 2018 Nobel Prize optical trap. Focused Gaussian laser beam gradient forces trap micro-particles and counter thermal Brownian diffusion.

Calculate optical properties, simulate light behavior, and explore fascinating physics of light.

Calculate orbital velocity, Keplerian period, and gravitational escape speed around celestial bodies. Analyze Low Earth Orbit, GPS altitudes, and Geostationary synchronization.

Visualize and analyze waveforms in real-time. Generate signals, adjust parameters, and explore waveforms.

Estimate minimum PCB trace width for a given current, copper thickness, and temperature rise.

Kinetic museum wave array. Independent pendulums with calibrated lengths execute serpentine traveling waves, choreographing standing waves and unified reconstitution.

Transparent plastics and tempered glass appear perfectly clear to our eyes, yet conceal massive internal structural stresses. When placed between crossed polarizers, anisotropic stress splits light...

Zoom into a leaf: light hits chloroplasts, CO₂ slips in through stomata, water arrives from the roots — and sugars plus the oxygen you're breathing come out. Drive it with light and CO₂ and find th...

The single-celled organism Physarum polycephalum (slime mold) and fungal mycelium have no brain or neurons, yet they solve complex mathematical mazes, Steiner tree networks, and traveling salespers...

Calculate common physics formulas: motion, forces, energy, and more. Select a formula to begin.

Comprehensive plant database with real-time data from multiple sources. Search for any plant to get detailed information.

Four boundary types, four very different landscapes: spreading ridges, subduction volcanoes, Himalaya-scale collisions and stick-slip transform faults — with earthquakes and mantle convection drivi...

Calculate electrical power values with multiple calculation modes. ⚠️ Educational purposes only — consult licensed electrician for actual installations.

Interactive optical bench simulating chromatic dispersion, Snell's law refraction, and total internal reflection (TIR) through a triangular prism.

🔬 A comprehensive suite of ecological calculations for researchers, environmental scientists, and conservation professionals. Includes statistical analysis, biodiversity metrics, and ecosystem mod...

Simulate parabolic ballistic trajectories in real time across different planetary gravitational fields. Computes flight time, apex altitude, total ground range, and impact velocity.

Analyze atmospheric water vapor psychrometrics using Magnus-Tetens formulas. Calculate exact Dew Point ($T_{dp}$), saturation vapor pressure ($e_s$), moisture humidity ratio ($W$), and surface cond...

Calculate electromagnetic photon energy ($E = h\nu = hc/\lambda$), momentum ($p = h/\lambda$), and matter wave de Broglie wavelengths across the entire electromagnetic radiation spectrum.

Quantum optics delayed-choice experiment. Observe wave interference, wavefunction collapse via which-way detectors, and quantum erasure recovery.

Unlike a classical binary bit (which is strictly 0 or 1), a quantum qubit exists as a continuous vector pointing anywhere on the 3D Bloch Sphere. Apply quantum gates ($H$, $X$, $Z$, $S$), observe c...

According to classical physics, the Sun should not shine! Its core temperature (15 million Kelvin) provides only ~1 keV of kinetic energy—ten times too weak to overcome the 1,000 keV electrostatic ...

Quantum mechanical wavepacket simulator solving the time-dependent Schrödinger equation across an impenetrable classical potential barrier.

Model exponential nuclear decay, remaining isotope fractions, and radiometric carbon dating via the fundamental decay law $N(t) = N_0 (1/2)^{t / t_{1/2}}$.

τ = R × C. A capacitor charges to ~63% in one τ and ~99% in 5τ. Cut-off of a first-order RC low-pass is fc = 1 / (2πRC). R in ohms, C in farads (enter µF).

Decode resistor color bands into resistance values. ⚠️ Educational only — verify with multimeter.

Calculate the dimensionless Reynolds number ($\text{Re} = \frac{\rho v D}{\mu}$) for internal pipe flow and aerodynamics. Visualize laminar streamline transitions into chaotic turbulent vortices.

Will the link work? Radio needs more than line of sight — it needs a clear ellipse of space around the beam, and the Earth quietly bulges up into it. This adds up every gain and loss in the chain, ...

Answer a few questions about your rock and get an identification — with visual examples and properties

Zoom from the Planck length (10⁻³⁵m) to the observable universe (10²⁷m). Drag the slider to see where you exist in the full scale of reality.

August Toepler's 1864 Schlieren photography system. Visualizes invisible thermal convection plumes and supersonic shockwaves via refractive index gradients.

Generate creative, hands-on science experiment ideas for all ages. Perfect for students, teachers, and curious minds!

Generate science quiz questions and test your knowledge with fun facts.

Build your science study list. Add topics and notes, then test yourself by hiding the notes. Saved locally in your browser.

Convert between common scientific and everyday units — length, mass, temperature, energy and pressure. Runs entirely in your browser.

Work through the scientific method. Enter your experiment idea and generate a structured outline.

Investigate ocean physics and the thermodynamic equation of seawater (TEOS-10). Calculate in-situ density ($\rho$), freezing point depression ($-1.91^\circ\text{C}$), sound speed ($c$), and thermoh...

Predict germination time based on seed type, temperature, and environmental factors using USDA, UC Davis, and university research data. This tool is supported by user contributions .

Soil pH and type determine nutrient availability and plant success. Match plants with their preferred conditions. This tool is supported by user contributions .

Essential for solar/off-grid setups: Calculate the right inverter size for your needs. Always consult a professional before installation!

Estimate solar panel requirements for your energy needs. Educational tool only — always consult a professional installer.

Interactive 2D simulation of the Solar System. Adjust time speed and scale, toggle orbits and labels, click planets for details.

John Scott Russell's 1834 hydrodynamic flume exhibit. Simulates the Korteweg–de Vries (KdV) equation where nonlinear steepening balances dispersion to form permanent solitons.

Precision wet-lab chemistry solver for serial dilutions ($C_1 V_1 = C_2 V_2$) and molarity-to-mass conversions ($\text{Mass} = M \times V \times \text{MW}$) with step-by-step bench pipetting protoc...

Calculate sound pressure level (SPL dB) drop over distance using the acoustic inverse-square law $L_2 = L_1 - 20\log_{10}(r_2/r_1)$, acoustic pressure in Pascals, and NIOSH/OSHA safe daily exposure...

See how mass warps the fabric of spacetime. Drag the mass slider to watch gravity bend space, slow time, and curve the paths of light.

Series adds ohms; parallel is the reciprocal sum. Never present an amp with a lower load than it is rated for — that is how output stages die. Passive crossovers are not modelled.

Calculate relativistic time dilation, length contraction, and kinetic energy via Einstein's Special Relativity equations. Compare spaceship crew time against stationary observer time.

One substance, three behaviours: a vibrating lattice (ice), molecules that slide but stick (water), and a fast free-for-all (steam). Drag the temperature and watch the same particles reorganise — w...

Industrial steam table thermodynamics (IAPWS formulation). Calculate saturation pressure ($P_{sat}$), specific enthalpy ($h$), entropy ($s$), specific volume ($v$), and latent heat ($h_{fg}$) for s...

In classical engineering, noise is the enemy. But in non-linear physics and sensory biology, Stochastic Resonance proves that adding the exact right amount of random noise allows a sub-threshold, i...

Convert body weight between stone & pounds, pounds, kilograms and grams. One stone is 14 lb; one avoirdupois pound is exactly 0.45359237 kg.

Calculate IPv4 subnets, network boundaries, usable host ranges, and binary bit allocation. Essential for cloud VPCs, DevOps, and network routing.

Type-II high-temperature superconductor cryogenic lab. Explore Meissner effect magnetic field expulsion and quantum flux pinning levitation.

Close-enough tap drill ≈ major diameter − pitch (75% thread). Metric coarse plus a few UNC sizes. For production work use the machinist’s table for your material.

The ground under you is moving right now. Pick a place and its tectonic plate and this rotates it about the plate's Euler pole — the real way plate motion is described — to give the present-day spe...

High-frequency Tesla coil discharge globe. Noble gas ionization streamers branch from the central electrode and focus to your touch via capacitive coupling.

The universe is governed by a handful of numbers. Change any one of them slightly — and atoms, stars, chemistry, and life cannot exist. Why these numbers?

Nothing "curves" in the air — but on a rotating planet, straight motion looks curved. Throw a ball across a spinning disk, then watch the same physics organise hurricanes: right-deflected in the no...

Light is a loan with interest. Museums cap both instant lux and lux-hours per year. Pick a material class, the gallery level and the hours the case is lit. The plaque says whether the year is still...

Does observation change reality? Explore the measurement problem, Schrödinger's cat, and the role of the observer in quantum mechanics.

Explore wave-particle duality, superposition, and the measurement problem. Fire particles through slits and watch reality behave impossibly.

Calculate heat transfer, efficiency, entropy, and explore thermodynamics principles. Essential tool for physics, engineering, and chemistry.

Two kinds of people watch the tide: sailors who need enough water under the keel, and everyone crossing a causeway, ford or sandbar who needs the water gone. Give it one high water and one low wate...

From the Big Bang to the heat death of the universe. Slide through 13.8 billion years of cosmic history and see how reality unfolded.

Calculate torsional stiffness ($k_t = \frac{GJ}{L}$), natural angular frequencies ($\omega_n = \sqrt{k_t/I}$), and critical whirling RPM. Analyze engine harmonic orders ($1\times, 2\times, 3\times,...

Simulate the theoretical physics of the triangular TR-3B aerospace platform. Calculates Mercury-based Magnetic Field Disruptor (MFD) plasma acceleration, inertial mass reduction percentage, and sup...

Estimate transformer size for electrical loads. ⚠️ EDUCATIONAL ONLY — Always verify with a qualified engineer and local standards.

Alan Turing's 1952 morphogenesis simulator. Nonlinear chemical reaction-diffusion equations generating biological spots, stripes, and coral textures.

40 kHz ultrasonic standing wave acoustic trap. Non-contact levitation of micro-beads and liquid droplets suspended in mid-air at acoustic pressure nodes.

Investigate acoustic wave mechanics in water. Calculate high-precision sound velocity ($c \approx 1,482\text{ m/s}$, 4.3× faster than air), bulk modulus incompressibility ($K_s = \rho c^2 \approx 2...

High-precision bidirectional converter across engineering, data storage, scientific physics, and everyday measurements.

Six of the universe's deepest mysteries run live as geometry: three-body chaos, curved spacetime & black-hole lensing, the centreless expansion, the golden angle, emergent life and fractal infinity.

Electrostatic museum exhibit. Rubber belt triboelectric charge transport accumulates up to 400 kV on the metal dome, firing high-voltage atmospheric sparks.

Design mechanical vibration isolators and shock mounts using force transmissibility ($T_R$). Calculate required static deflection ($\delta_{st}$), isolation efficiency ($\eta$), and operating frequ...

Virtual measurement and leveling tools using device sensors. Requires camera and motion sensor permissions.

Vout = Vin × R2 / (R1 + R2). R1 is the top resistor from the supply; R2 is the bottom resistor to ground. Unloaded — a low-impedance load pulls the output down.

Estimate voltage drop across a conductor run. Educational only — always verify with a qualified electrician and local standards.

Watch Earth's water engine run: the Sun lifts water from the ocean as vapour, clouds build, rain falls, and every drop finds its way back to the sea. Step through the four stages or let it flow.

Investigate water's famous thermodynamic density anomaly ($\rho_{max}$ at $3.98^\circ\text{C}$). Explore negative thermal expansion, the $+9\%$ ice phase transition volume expansion, and ecological...

Investigate water's molecular dipole moment ($\mu = 1.854\text{ Debye}$) and huge dielectric permittivity ($\epsilon_r \approx 80.1$). Model Debye relaxation ($\epsilon^*(\omega) = \epsilon_\infty ...

Assess water hardness and mineral stability using the Langelier Saturation Index ($\text{LSI} = \text{pH} - \text{pH}_s$) and Ryznar Stability Index ($\text{RSI}$). Predict calcium carbonate precip...

Investigate water's auto-protolysis equilibrium ($2\text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{OH}^-$). Discover why neutral water is $\text{pH } 7.00$ only at $25^\circ\text...

Navigate water's complete thermodynamic $P$-$T$ phase space across Solid, Liquid, Vapor, and Supercritical regimes. Explore the Triple Point ($0.01^\circ\text{C}, 611.65\text{ Pa}$), Critical Point...

Explore water's extraordinary cohesive hydrogen-bond surface tension ($\sigma = 72.86\text{ mN/m}$). Calculate Jurin's Law capillary rise ($h = \frac{2\sigma\cos\theta}{\rho g r}$) and Young-Laplac...

The hardest problem in science. Explore the mystery of subjective experience — how does matter become aware? Interactive exploration of the leading theories.

Spoke length is a three-dimensional problem: the spoke runs from a hole in the hub flange, sideways to the rim centreline and around by however many crossings you lace. Get it wrong by two millimet...

Air molecules scatter sunlight in every direction — and short wavelengths scatter about 4× more than long ones. Slide the Sun down and watch the same physics hand the sky back as a sunset.

The deepest question philosophy has ever asked. Explore the mystery of existence itself — why does anything exist at all?

Supersaturated alcohol vapor chamber detecting cosmic muons and subatomic radioactive decay tracks via ion-nucleated condensation.

NWS/JAG/TI wind-chill (2001): valid when air is ≤ 10 °C and wind ≥ 4.8 km/h. It estimates how cold exposed skin feels — not a frostbite timer, and not for indoor fans.

Air is a moving floor. Point the nose where you want to go and the wind quietly carries you somewhere else, so every navigation log starts with the same triangle. This solves it exactly — heading t...

Waves are built by three things: how hard the wind blows, how far it blows over open water, and how long it keeps blowing. This works out which of the three is holding your sea state back, using th...

Professional wire sizing calculator for electrical installations with NEC/IEC compliance checks and safety recommendations.

An interactive world map with all 195 countries (UN members + observers) — every marker is a capital city. Explore flags, capitals and continents, then quiz yourself three ways: find the country on...

Type a point in any system and the other two update instantly, with the point drawn in 3D and its radius and angles traced out so you can see what each number means. Switch between the physics (ISO...

Pick two objects — point, line or plane — and get the shortest distance, the intersection point or line, the angle between them and the closest points, all drawn in 3D. Handles parallel, skew, coin...

Pick a solid, type its dimensions and watch it rebuild in 3D. Get the volume, total and lateral surface area, capacity in litres and gallons, diagonals and slant heights — with the formula and work...

Enter up to three vectors and see them as glowing arrows in 3D. Instantly get the dot product, cross product, angle between them, projection, parallelogram area, scalar triple product and parallele...

Comprehensive number theory laboratory: Explore prime numbers, factorization, modular arithmetic, sequences, and advanced mathematical properties. Perfect for students, educators, cryptography enth...

Master percentages with advanced calculations, visualizations, and real-world applications. From basic math to financial analysis!

Solve equations instantly. Type any equation and click Solve.

In real-world data — expenses, populations, invoices — a leading 1 shows up about 30% of the time and a 9 under 5%. Paste a column of numbers and this scanner compares their first digits with the l...

Expand any binomial such as (2x + 3)⁵ or (x − 1/y)⁸ term by term, with Pascal's triangle, the binomial coefficients, a “find term k” locator and Newton's generalised (1 + x)ⁿ approximation for frac...

Type any expression and see it solved one operation at a time with the reason for each step — no calculator tricks, no guessing. Then take the 5-question practice round with worked solutions. Every...

Work with derivatives and integrals. Enter a function of x, choose operation, and generate step‑by‑step results.

The workhorse test for counting data: does an observed distribution match what theory predicts (goodness of fit), and are two categorical variables related (contingency test)? Live contributions, χ...

Angle between hour and minute hands. Minute hand = 6° × minutes. Hour hand = 0.5° × (60×hours + minutes). The smaller angle is min(θ, 360 − θ).

Read the hands, set the clock yourself, and work out elapsed time — three modes, five questions each, with instant feedback. The clock is drawn locally; nothing leaves your device.

Take any positive whole number: halve it if even, triple-and-add-one if odd. Every number ever tried falls into the 4-2-1 loop — nobody has proved why. Chart any starting value (BigInt-sized), meas...

Type any complex function f(z) and see it as a 3D landscape: height is |f(z)| or Re/Im, colour is the phase (domain colouring). Zeros become valleys, poles become towers. Evaluate f at any point, l...

Perform operations with complex numbers in rectangular (a+bi) and polar (r∠θ) forms. Visualize results on the complex plane with step-by-step solutions. ✅ Supports: + − × ÷ √ ^ log sin cos conjugat...

Every number, rational or irrational, unfolds into a chain of whole numbers: a₀ + 1/(a₁ + 1/(a₂ + …)). Cut the chain early and you get the best fraction there is for the size — 355/113 for π, Pell ...

WORKING CALCULATOR for Computer Science & Mathematics. Real calculations for set theory, combinatorics, and logic. Everything works instantly!

Solve algebraic equations step-by-step. Supports linear, quadratic, and cubic equations. Try examples below!

Work out your exact age — or the time between any two dates — in years, months, weeks, days, hours, minutes and seconds. Shows your next birthday countdown, the weekday you were born, your zodiac s...

COMPLETE MATH PREP - Generate practice problems with step-by-step solutions. Track your progress across 500+ questions covering all major topics.

Calculate powers, roots, and exponential functions with detailed steps and visualizations. Perfect for students learning algebra and calculus.

List the factors and multiples of any number, then practise finding the highest common factor, lowest common multiple and factor/multiple facts.

Enrico Fermi walked into interviews and produced piano-tuner counts out of thin air: chain a handful of round numbers together and the answer lands within a factor of ten of the truth. Pick a class...

Calculate arithmetic and geometric sequences and series. Includes step-by-step solutions and visual representations.

Sin = Opposite / Hypotenuse Cos = Adjacent / Hypotenuse Tan = Opposite / Adjacent

Master fractions with calculations, visual representations, and step-by-step explanations. Perfect for students learning fractions!

Solve any triangle from three known parts — sides, angles, or both. Works out the missing sides and angles, area, perimeter, in-circle and circum-circle, shows the law-of-sines or law-of-cosines st...

Type any z = f(x, y) formula and watch it become a spinning 3D mountain range. Safe built-in math parser (no eval), orbit/zoom controls, height colormaps and a random-function dice for beautiful ac...

Find the greatest common factor, least common multiple and prime factorisation of one or more integers. Enter a single integer to also see whether it is prime and its neighbouring primes. Euclidean...

Calculate areas, perimeters, and volumes for common shapes. Choose a shape, enter dimensions, and get results with formulas shown.

Calculate the area, perimeter, or volume of common shapes.

Calculate weighted grades, predict final scores, and see what you need to achieve your target grade.

Convert between hexadecimal, decimal, binary, octal, and ASCII with bitwise operations. Essential for developers, modders, and reverse engineering!

Calculate GPA for universities worldwide. Supports multiple grading systems and conversions.

Paste a table of x,y readings and ask for values in between. Linear interpolation rides the segments; the Lagrange polynomial threads every point at once and prints its expanded formula. Goes backw...

Paint 1s and don't-cares onto a two, three or four-variable K-map and it finds the prime implicants for real — no eyeballing wraps — returning a minimal sum-of-products or product-of-sums with ever...

Surfaces that shouldn't exist: a Möbius strip with adjustable twists, a Klein bottle (inside IS outside), and torus knots you design with p/q sliders. Points, wireframe or solid candy render.

Perform comprehensive linear algebra operations with step-by-step solutions, matrix visualization, and educational explanations.

Every linear-programming optimum lives on a corner. Build the feasible region from up to six inequality constraints, watch the objective line slide across it, and read the winning vertex straight o...

Type any 3×3 matrix and watch it smoothly warp space: the unit cube becomes a parallelepiped whose volume is the determinant, and real eigenvectors light up as the lines that only stretch. Computes...

Evaluate logarithms in any base, convert between bases, and solve for an unknown exponent. Shows the change-of-base working so you can follow it on paper.

See every step of long division — divide, multiply, subtract, bring down — then practise on a generated calculation with full remainder and check-back working. All local, nothing sent anywhere.

Fill a grid so every row, column and both diagonals add to the same magic constant. Generate perfect squares of any order 3–14 with the real historical algorithms (Siamese ladder, 4×4 complement, S...

Solve mathematical expressions, equations, and practice calculations. Supports arithmetic, algebra, trigonometry, and more!

Step beyond calculation into mathematical discovery. Visualize concepts, see proofs unfold, find connections humans have never seen.

Generate random maths flashcards for quick practice. Perfect for studying, teaching, or mental math warm-ups. 🎯 Interactive • Timed practice • Multiple topics • Progress tracking

Work out the mean, median, mode and range of a data set, see the full working, and learn when each average is the right tool. 5 rounds, instant feedback, all on your device.

Paste numbers separated by commas, spaces or new lines. Sample standard deviation uses n − 1 (Bessel); population uses n. Mode lists every most-frequent value.

A 60-second arithmetic workout with three difficulty levels, streak bonuses and a review of every question you missed. Sharpens everyday number sense — tips, change, discounts.

Paste any ordered series — sales, signups, call volumes, temperatures — and every average you can pick (simple, exponential, weighted) is scored against the data's own history before it dares to pr...

Start from a ten-triangle seed and watch an inflation rule grow a patch that can never repeat: thick and thin rhombi assembled from Robinson triangles, exactly the construction Roger Penrose used t...

Work out the percentage increase or decrease between two numbers, plus reverse percentages and a worked price-change example.

Explore the five Platonic solids and their Archimedean cousins in shaded 3D. Morph any solid into its truncation, overlay its dual, and get exact volume, surface area, in/mid/circumradius and dihed...

Beyond quadratics, closed-form roots die at degree five — so solve numerically instead. Type any polynomial up to degree 8 and Durand–Kerner marches all of its complex roots into existence simultan...

Break any number into its prime factors with a full working ladder, learn the divisibility rules, then practise finding the next prime factor yourself. Primes are the building blocks of every whole...

Calculate probabilities for dice, cards, distributions, and real-world scenarios.

Your gut feeling about chance is usually wrong — prove it to yourself. Simulate the Monty Hall problem, the birthday paradox and coin-flip streaks with thousands of instant trials.

Name the two first-branch events and their conditionals, and the whole tree draws itself: every path probability, the marginal for each second-stage outcome, and the famous flip — P(A | B) computed...

Find the missing side of a right-angled triangle with the Pythagorean theorem — plus the area, perimeter and both acute angles.

Solve ax² + bx + c = 0 with the quadratic formula — real or complex roots, with every step shown.

π rad = 180°. Also shows revolutions and a reduced π-fraction when it is close to a simple multiple of π.

Solve a/b = c/d for the blank, simplify a ratio, and scale a recipe-style mix. Leave exactly one of A, B, C, D empty. Cross-multiply: A × D = B × C.

Type any function, drag the number of rectangles, and watch the classic left/right/middle/trapezoid sums close in on the true integral. Live shaded plot, error against a high-precision reference, a...

Convert numbers to Roman numerals and back, with a step-by-step breakdown of how each numeral is built. Handles 1–3,999 in standard notation and up to 3,999,999 with overline (vinculum) notation. I...

Three legendary ways to hunt for where f(x) = 0, run side by side with every iteration, error and failure mode on display: guaranteed-but-slow bisection, lightning-fast Newton–Raphson (and exactly ...

Master rounding rules and quick estimation. Round any number to a chosen place, then estimate answers to real-life word problems with 5-round quizzes and full working.

Full-featured scientific calculator with trigonometry, logarithms, powers, and memory functions. Works offline.

Interactive scientific formula calculator with detailed explanations, 3D visualizations, and step-by-step solutions. Perfect for students and professionals in STEM fields.

Convert a number to scientific / engineering notation and round to significant figures. 1.23 × 10⁴ is 12300. Trailing zeros in 1000 are ambiguous — say how many sig figs you want.

Find any term and the running sum of arithmetic or geometric sequences, test a geometric series for convergence, and see the working for the formula you used.

Click vertices onto a grid (or type coordinates) and get the exact area of any polygon — even weird L-shapes, arrowheads and plots of land — using the surveyor's shoelace formula, with the full cro...

Feed it two or three linear equations and watch elimination, substitution or Cramer's rule unwind line by line in exact fractions — never rounded decimals. Parallel and identical lines get diagnose...

Interactive math visualization: Plot functions, find roots, compute derivatives/integrals, solve equations, and create beautiful graphs. Perfect for students, teachers, and professionals.

Spin any curve y = f(x) around the x- or y-axis and watch the 3D solid form. Get the volume by disc/washer and shell methods, the surface area and centroid, with an optional inner curve for washers...

Fill in any two of speed, distance and time; the third is calculated. Swap units without changing the physics: metres, kilometres, miles, knots, hours, minutes, seconds.

V_sphere = 4/3 π r³, A = 4 π r². Cylinder π r² h. Cone (1/3) π r² h. Enter radius and height in the same units; volume comes out in those units cubed.

Comprehensive statistical analysis tool with descriptive statistics, probability distributions, hypothesis testing, and data visualization. This tool is supported by user contributions .

Four jobs in one desk: strip perfect squares out of a root with every factor shown, collect like surds across an expression, expand (a+b√c)(d+e√c) the FOIL way, and rationalise a denominator by its...

Type any surface z = f(x, y) and see its curvature painted onto it: warm where it bends like a dome (K > 0), cool where it curves like a saddle (K < 0). Move a probe to get the tangent plane, norma...

Drill the 1–12 times tables with instant feedback, streak tracking and a review of the facts you get wrong. Includes a full 12×12 grid and memory tricks. Everything runs in your browser — no sign-u...

Type any 3D vector field F = (P, Q, R) and see it as a forest of glowing arrows with flowing particles. Calculates divergence and curl at any point, both numerically and visually, and integrates th...

Type two lists and watch the Venn diagram draw itself — union, intersection, symmetric difference and per-zone items are listed.

An untuned 808 sub-bass creates mud, phase cancellation, and clashes with your melodic sample. Select your song's root key to find the exact fundamental frequency (Hz), room wavelength standing nod...

Generate pure acoustic tones, test speaker frequency responses, and monitor live audio waveforms using the Web Audio API.

Generate scientifically tuned binaural beats and isochronic frequencies using pure Web Audio synthesis. Entrain your brainwaves for laser focus, flow state, deep meditation, or rapid sleep. 🎧 Head...

Instant, free online BPM Tap Counter (Pro) tool. No signup required.

Find capo placement for key transposition, chord conversion, and song adaptation. Supports sharps/flats, multiple fret options, and tuning adjustments.

Identify chords from selected notes. Perfect for songwriters and beginners!

Build, analyze, and explore chord progressions for songwriting. Perfect for musicians and composers!

Sing along to Christmas classics with synchronized lyrics, pitch detection, and festive backgrounds! 🎤 Features: 50+ carols, pitch meter, key changer, duet mode, recording

Pick any key to see its relative minor, the closely related keys either side of it on the circle, and the seven diatonic chords built from that scale. Everything runs offline in the browser.

Convert tempo to delay, reverb pre-delay and LFO times. Note length in milliseconds = 240,000 ÷ BPM ÷ denominator (crotchet = 4). Dotted is × 1.5; triplet is × ⅔.

Equal-temperament fret rule: distance from nut to fret n = L × (1 − 1/2^(n/12)) where L is scale length. 12th fret is the octave (halfway). Not a CNC file.

Muddy hip hop mixes happen when competing instruments fight for the same acoustic frequency space. Select any common mix conflict pair to visualize precise complementary boost & notch carving curve...

Compressors that aren't mathematically timed to your beat either choke punchy transients or pump unnaturally. Calculate tempo-synced Attack, Release, and Hold times for kick-to-808 sidechain duckin...

Get detailed care instructions with maintenance schedules, required tools, and professional tips for your specific instrument.

Reference notes for tuning your instrument. Educational only — verify with your ear or a professional tuner.

Essential for musicians: Learn to identify intervals by ear. Perfect for singers, composers, and anyone learning music theory!

Recreate the legendary gritty texture of golden era hip hop and chill lo-fi beats. Dial in 12-bit sampler downsampling (E-mu SP-1200, Akai S950), cassette tape wow/flutter pitch drift, and analog v...

Check a sample’s end-to-start jump and slope mismatch before setting a loop in your sampler.

Use measured integrated LUFS and true peak to plan a gain change and see whether your chosen peak ceiling permits it.

The secret to head-nodding hip hop bounce lies in micro-timing: Roger Linn's legendary MPC 16th-note swing formula, J Dilla's unquantized lazy pocket, and modern Drill swing offsets. Calculate exac...

Master the lyrical mechanics of golden era and modern technical rap. Map your syllables across a 16-slot 4/4 measure grid to lock your flow into the pocket, identify multi-syllabic vowel rhyme sche...

Explore scales, chords, and intervals on a virtual piano — hear how they sound and see the theory behind them

Transpose chords, melodies, and entire progressions between keys. ⚠️ EDUCATIONAL TOOL — Verify with music teacher or professional resources.

12-tone equal temperament: f = f₀ × 2^(n/12). Default A4 = 440 Hz. MIDI note 69 is A4. Period = 1/f.

Normalize mono or stereo samples to a chosen sample-peak ceiling, with linked-channel gain and a downloadable 24-bit PCM WAV.

Precise audible & visual metronome with subdivisions, tap tempo, and tempo presets. ⚠️ Enable sound in your browser

Learn fundamental recording techniques. ⚠️ Educational only — always verify with professional resources.

Uncalculated reverb washes out hip hop vocals and turns snappy snares into a muddy blur. Calculate tempo-synced pre-delay (giving the upfront vocal clarity before reverb begins) and precise decay t...

Generate rhythm patterns for practice and composition. ⚠️ Educational only — verify with professional resources.

Calculates exact mathematical slice cue points and sample frame offsets for 16-pad hardware samplers (MPC, SP-404, Maschine) and DAWs. Slice 1-bar, 2-bar, or 4-bar sample loops into clean musical c...

Translate a measured timing offset into DAW sample nudges, acoustic path difference, and predicted comb-filter notches.

Practice scales in different keys. Educational only — always verify with a music teacher or professional resource.

Generate detailed sheet music references with proper notation guidance. ⚠️ Educational only — always verify with a teacher or professional resource.

Brainstorm song ideas, lyrics, and structure. ⚠️ Educational only — always verify with a teacher or professional resource.

Measure stereo correlation, side energy, and mono fold-down loss from your mix without uploading it.

Create tempo maps for musical compositions with BPM calculations and time conversions. Educational tool for musicians and composers.

Craft the iconic bouncing hi-hat patterns of modern Trap, Atlanta bounce, and UK/NY Drill. Program 1/32nd rolls, 1/24th triplet flurries, ascending velocity ramps, and pitch drops with live interac...

Interactive music knowledge challenge: Test your expertise across theory, history, instruments, and pop culture. Complete with scoring, explanations, and shareable results!

In golden era hip hop and modern boom-bap, pitching a vinyl sample directly changes its tempo (varispeed resampling). Calculate the exact mathematical relationship between Semitone pitch shift, cen...

Mix YouTube videos live like a professional DJ. Crossfade between tracks, apply effects, and create seamless mixes. 🎧 Live mixing • Crossfader • EQ • Effects • YouTube integration

Optometrists’ rule for screen strain: every 20 minutes, look at something 6 metres (20 feet) away for 20 seconds. This runs the cycle for you — start it when you sit down to work.

Anion gap with albumin correction and delta ratio, corrected sodium for hyperglycaemia, corrected calcium for albumin, calculated osmolality with the osmolar gap, and the urine anion gap. SI or US ...

The five components at 1, 5 and 10 minutes with the trend across all three, the resuscitation bands, and the caveats about prematurity. Held in memory only — nothing is written to this browser.

pH, PaCO₂ and bicarbonate classified into the primary disorder with the expected compensation checked against Winter's formula, plus A-a gradient, P/F ratio and respiratory failure typing. kPa or m...

Most UK powders use 1 level scoop per 30 ml of water (check the tin). Water first, then powder. This is arithmetic — NHS mixing and sterilising steps still apply, and never microwave a bottle.

Babies run on wake windows — how long they can stay awake before they need to sleep again. It changes fast in the first year and getting it wrong by half an hour is usually the difference between a...

Home-monitor numbers compared with NHS adult clinic bands (and a note on AHA). One reading is not a diagnosis. Seek urgent help for chest pain, one-sided weakness, or a sudden severe headache. This...

Calculate your Body Mass Index (BMI) with accurate WHO classification. BMI is a simple screening tool for weight categories that may lead to health problems.

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using scientifically validated formulas.

Estimate your body fat percentage using the U.S. Navy method and understand your fitness level.

Estimate body surface area with Mosteller, Du Bois and Haycock formulae from height and weight. Used for some drug doses and cardiac index. Educational only — never override a prescribed dose.

Estimate daily calorie needs with BMR calculation, weight goals, and macronutrient breakdown. Auto-saves profiles for quick access.

Rough weeks to a goal weight from a daily calorie deficit. Uses ~7,700 kcal per kg (about 3,500 kcal per lb). Real bodies adapt — this is a sketch, not a promise, and not medical advice.

Stroke risk and bleeding risk for atrial fibrillation side by side, with the sex-adjusted anticoagulation thresholds, the Friberg annual stroke rates, and the modifiable-risk checklist that HAS-BLE...

Track your child's growth, compare with WHO percentiles, and monitor development milestones.

Holliday-Segar maintenance, dehydration deficit replacement with the 8-hour split, and burn resuscitation with a Rule-of-Nines TBSA helper that counts down the first-8-hour window from the time of ...

100% offline emergency triage protocols, acoustic CPR rhythm metronome, water survival calculator, and optical SOS distress beacon. Operates completely without internet during grid blackouts and na...

Calculate your personalized daily water intake needs. Track your progress throughout the day!

Estimate a daily protein target from body weight and how hard you train. Sedentary adults often sit near 0.8 g/kg; strength athletes commonly use 1.6–2.2 g/kg. Not a prescription — kidney disease n...

Race-free CKD-EPI 2021 eGFR plus Cockcroft-Gault creatinine clearance side by side, with KDIGO G-stage and the renal dosing bands that hang off them. Runs offline in your browser.

Calculate your comprehensive fitness score with detailed insights and personalized recommendations. Based on scientific health metrics and activity analysis.

Adult and pre-verbal paediatric GCS with the 2014 wording, "not testable" handled properly, the E-V-M string for the notes, and the NICE deterioration thresholds. Nothing is stored or sent anywhere.

Convert HbA1c (%) to estimated average glucose with the NGSP/DCCT formula (eAG mg/dL = 28.7 × A1c − 46.7). Educational only — lab methods differ (IFCC mmol/mol vs NGSP %), and this is not a diagnosis.

Calculate Karvonen training zones, VO₂ max estimates, heart rate variability (HRV), and recovery metrics. Professional-grade analytics for athletes!

Get a comprehensive analysis of your ideal weight range using multiple scientific formulas and personalized factors.

Allergens hide behind nicer names: “caseinate” is milk, “arachis oil” is peanut, “hydrolysed vegetable protein” is often wheat, and E220–E228 are sulphites. Paste an ingredient list — from a packet...

Pick a 16:8, 18:6, 20:4 or custom fast and see today’s eat-from / eat-until times. Educational scheduling only — not medical advice, and not for anyone who is pregnant, under 18, or has an eating-d...

mL/h ⇄ drops/min for any giving set, weight-based dose rates from the concentration in the bag, and time-to-empty with the clock time it finishes. Everything works out on your device.

Estimate your lean body mass using multiple formulas and get detailed body composition analysis.

MAP ≈ (systolic + 2 × diastolic) / 3, plus pulse pressure. A resting MAP near 70–100 mmHg is often cited as adequate organ perfusion. This is arithmetic, not a diagnosis — chest pain or a very high...

Estimate your metabolic age based on your Basal Metabolic Rate (BMR) compared to population averages. 💡 Lower metabolic age indicates better metabolic health

Royal College of Physicians National Early Warning Score 2 with both SpO₂ scales, the single-parameter-of-3 rule and the RCP escalation table. Shows which band each observation landed in so the sco...

Instantly estimate your maximum lifting capacity across multiple formulas.

Estimate ovulation and the fertile window from the first day of your last period and your typical cycle length. Sperm can survive up to five days, so the window starts before ovulation. Calendar me...

Estimate your due date from the first day of your last period, conception date, IVF transfer or a scan-dated due date. See how many weeks and days pregnant you are today, the current trimester, key...

IOM/NAM ranges by pre-pregnancy BMI for a singleton: underweight 12.5–18 kg, healthy 11.5–16 kg, overweight 7–11.5 kg, obese 5–9 kg. A sketch for conversations with a midwife — not a target you mus...

QTc (Bazett) = QT ÷ √(RR), with RR = 60 / heart-rate. Also shows Fridericia (QT ÷ RR⅓). Educational arithmetic from numbers you type — not an ECG, not a diagnosis. Chest pain or syncope needs emerg...

Calculate optimal wake-up times based on 90-minute sleep cycles for better rest. No affiliate links - this site is supported by user contributions .

🏋️ Achieve your goals: Calculate protein, carbs, and fats for weight loss, muscle gain, or maintenance. Get personalized meal plans and food suggestions.

A pack a day is a used car every year. Set what you actually smoke, pick a quit date, and watch the money timeline — plus the recovery milestones your body hits along the way.

Convert steps walked to calories burned with precision. Calculate energy expenditure based on steps, weight, and walking pace. See equivalent activities and track progress toward daily goals. This ...

Classic Tabata is 8 rounds of 20 s work / 10 s rest (4 minutes). Phone speakers optional. If you prefer reduced motion, the digits still count without the pulse.

Nothing here cures tinnitus — no app does. What helps is not silence: a quiet, boring sound at or just below the pitch of the noise stops your brain listening for it. This makes those sounds on the...

UK units = ABV (%) × volume (ml) ÷ 1,000. The NHS low-risk guideline is 14 units a week, spread out, with several drink-free days. This is arithmetic, not medical advice.

Estimate your VO₂ Max — a measure of aerobic fitness. The higher the value, the better your cardiovascular endurance.

NICE NG246 uses waist ÷ height as a central-adiposity screen for adults with BMI under 35. Measure the waist at the midpoint between the last rib and the hip bone. Not a diagnosis.

Calculate your waist-to-hip ratio and see your health risk category based on WHO guidelines.

mg/kg to milligrams, milligrams to millilitres at the strength you have, split across divided doses, with a hard-stop check against the maximum dose you set. No account, no data leaves the page.

Tap the value of each arrow as you shoot and this keeps the running total, your Xs and 10s, and how far through the round you are — the way scorers count at the line.

The official World Athletics scoring tables: type a performance in any event and get its points, then watch the total build toward a world-class score. Times in seconds (or m:ss), jumps in centimet...

Rally scoring to 21, win by two — but a game can only go to 30. Tap a side to add their point and this handles the deuce, the game win, and the best-of-three match for you.

Stop doing bar maths in your head between sets. Enter the target weight, choose your bar and available plates, and see exactly which plates go on each side — drawn to scale — plus a sensible warm-u...

The slash line every hitter lives by — batting average, on-base and slugging, plus OPS — and the pitching numbers (ERA and WHIP). Enter a box score and get the exact formulas and a read on what the...

Type in a box score and get the metrics the analysts use: Game Score, effective and true shooting percentage, points per shot and assist-to-turnover ratio — all with the exact formulas and a plain-...

Work out fractional odds as a decimal and a probability, and see exactly what an each-way bet returns — whether your horse wins, only places, or finishes nowhere. The stake, odds and place terms al...

Works out what every gear on your bike actually does — how far one pedal turn takes you, what speed you will be doing at a given cadence, and which gears are duplicates you never need. The thing mo...

In bouldering, tops beat everything. Enter two climbers' results and this applies the ranking order — most tops, then fewest attempts to top, then most zones, then fewest attempts to zone — and dec...

Score a fight round by round using the official 10-Point Must System. Knockdowns and point deductions are applied automatically, with a live running total and winner projection.

Mid-fight maths for fans and cornermen. Enter the score so far and see exactly what each fighter needs in the remaining rounds — including whether a knockout has become the only route.

Score a single round against the four official criteria — clean punching, effective aggression, ring generalship and defence — in their correct priority order. Shows which criterion decided the round.

Work out whether an incident is a scoring knockdown or a slip, how the count runs, and what it does to the round score. Includes a live count timer at the official pace.

Paste a completed card and see the shape of the fight — momentum swings, the longest run of rounds, who finished stronger, and which rounds were decisive enough to change the result.

Live compubox-style punch counter. Tap as you watch to log jabs and power shots landed or thrown, and get instant connect percentages plus a work-rate comparison.

Full bout timer with authentic bell and ten-second clapper, generated live in your browser. Configure round length, rest interval and round count for sparring, training or scoring practice.

Compare your card against the official judges round by round. Highlights exactly where you disagreed, measures your agreement rate, and flags the swing rounds that decided the fight.

Enter three official cards and get the correct verdict — unanimous, split, majority, or draw. Handles every decision type including the frequently confused majority draw.

Find the correct division for any weight, check whether a fighter has made the limit, and see rehydration-clause and catchweight implications. Covers all seventeen professional classes.

See what a single game does to a rating. Enter both players' ratings and the result, and this gives the expected score, the exact rating change, the new rating, and the performance rating for that ...

The tie-breaker that decides tournaments. Add each match's runs and overs for and against, and this works out your aggregate Net Run Rate — applying the rule that a team bowled out is counted as fa...

Second innings, chasing a target: enter the score you are after, how far the chase has got, and see the current rate, the required rate, your projected total, and exactly how fast the run rate has ...

In each end, the team with the stone closest to the button scores one point for every stone nearer than the opposition's best. Enter each end and this keeps the running score to the last stone.

How many watts to hold 40 km/h up a 4% climb? Or what speed does your FTP actually buy you? This models the three forces a rider fights — rolling resistance, air drag and gravity — and splits your ...

Log each visit of three darts and watch your three-dart average climb. Handles the bust rules for you — scoring more than you have left, or leaving yourself on 1 — and tracks legs won across a sess...

Stood at the oche wondering how to finish? Type the score you have left and get the standard two- or three-dart checkout. Includes the full 2–170 checkout chart and a practice mode that hides the a...

Score a dive the way the judges do: enter the judges' marks and the degree of difficulty, and this drops the outliers and applies the official formula to give the dive its total.

Tally a driver's season under the current 2025 points system — 25 down to 1 for the top ten, 8 down to 1 for a sprint — and see the running total, points per round, and how it compares with a rival.

The run-in made simple. Put in where your team stands, how many games are left, and the points you are aiming for — a title, promotion, safety mark or a rival — and see exactly what the remaining f...

Enter your course handicap and your gross score for each hole, and this works out the shots you receive, your net score, and the Stableford points per hole — the friendly format where a blob costs ...

The World Handicap System in two steps. Work out a round's Score Differential (what actually feeds your handicap), then turn a Handicap Index into your Course Handicap and Playing Handicap for that...

A gymnastics score is difficulty plus execution. Enter the D-score, tick the deductions, and this works out the E-score (out of 10) and the final total.

Two halves, goals, and the two-minute suspensions that define the game. Tap to score, track each team's suspensions, and keep the running total.

Turn a goalie's box score into the numbers that matter: goals-against average, save percentage, and a win–loss record — with a read on how good they actually are.

Turn a lap time into an average speed and a full race duration, see how much each pit stop costs, and — if you have a rival's lap time — watch the gap grow lap by lap.

Four quarters, one point a goal. Tap a team to add their goals, advance the quarter, and keep a clean running score with the per-quarter breakdown.

Compare lifters across weight classes. Enter a bodyweight and total (or the three lifts) and get both the modern DOTS score and the classic Wilks score, so a 60 kg lifter and a 120 kg lifter can be...

Live Premier League data scraped from current online sources. Teams update automatically.

Enter one recent race you actually ran, honestly, and this predicts the rest, gives you the pace to hold per kilometre or mile, and turns it into the five training paces you actually need. Predicti...

Three quick reflex benchmarks in one place: how fast you react to a colour change (in milliseconds), how many clicks per second you can manage, and how accurately you hit moving targets. Personal b...

Generate a full league schedule where every team plays every other team — once, or twice home and away. The circle method guarantees no team plays twice in a round, and odd numbers get a bye.

The rowing machine's watts and your 500 m split are two ways of saying the same thing. Enter either and this works out the other, plus your speed and predicted times for the standard test distances.

Try 5, conversion 2, penalty 3, drop goal 3. Add up a score, or work backwards: give a points gap and this lists every combination of tries, conversions, penalties and drop goals that closes it — f...

Cadence, pace and stride length are locked together — fix any two and the third is forced. Fill in the two you know and this computes the rest, plus your steps per kilometre and total steps for a d...

Target time for a race distance → pace per km and per mile, plus even kilometre splits. Negative splits are a planning aid, not a training plan.

Faults add up fast: 4 for a knockdown, 4 for a refusal, and 1 for every second over the time allowed. Enter a round and get the total, then use a rival's faults and time to settle a jump-off.

The question every frame hinges on: can the player behind still win, and how many snookers do they need? Set the balls left on the table and the score, and this works out the points remaining, the ...

Turn a swim time into pace per 100 m, per length and full splits, then — if you have a 200 m and a 400 m test time — get your Critical Swim Speed and the training zones built around it.

Rally scoring to 11, win by two — no cap, so a deuce game can run long. Tap to score and it tracks games and the best-of-five (or seven) match for you.

Enter the pinfall for each roll and this scores the game for you — strikes and spares with the bonuses, and the tenth frame's extra balls, all handled automatically.

Score a match point by point with the correct rules handled for you: deuce and advantage, sets to six with a two-game lead, a seven-point tiebreak at six-all, and best-of-three or best-of-five matc...

Knock out a single-elimination draw in seconds. Pick how many teams, name them if you like, and get a seeded bracket with the right number of byes, in a form you can read or copy out.

Build a race-day plan: pick a distance, enter your swim pace, bike speed, run pace and transitions, and this gives you the time for each leg and your finish line.

Rally scoring to 25 (win by two, up to 30), with the fifth set to 15 — plus a rotation tracker: list your six players in serving order and they rotate every time the side that wins the rally was re...

The Sinclair coefficient lets lifters of different bodyweights be compared. Enter sex, bodyweight and total, and this computes the 2025–2028 Sinclair coefficient and Sinclair Total.

Every child gets a fair go. Tell it how many players, how many are on the pitch at once, and how long the game lasts, and it builds a substitution plan that shares the minutes out as evenly as poss...

Compare, learn, and pronounce essential survival phrases side-by-side across 10 of the world's most spoken languages with instant native audio speech synthesis.

Generate stylish bios for Instagram, TikTok, Discord, Twitter/X, and more — with fonts, symbols, and vibes

🚀 Ultimate literary toolkit: Analyze any text AND generate study materials. Perfect for students, teachers, and book lovers.

🚀 Ace your exams: Transform any topic into flashcards, practice quizzes, study guides, and mnemonics. Perfect for students, lifelong learners, and professionals.

AI-Style Summary Generator Generate intelligent summaries using advanced text analysis algorithms

Find every word you can make from your letters — from two letters up to the full anagram — with optional pattern matching.

Structure an essay or debate case before you write it. Lay out your thesis, the premises supporting it and the strongest objections, then score how well each one actually holds up.

Learn the 26 letters of English Braille by building cells dot by dot and decoding them. Each letter is a 2×3 grid of raised dots — once you see the pattern, the whole alphabet unfolds. All local, n...

Draft clear, professional business documents: memos, executive summaries, proposals, and meeting notes. Choose the document type, enter the purpose and key points, then generate a polished draft yo...

Generate Instagram, TikTok, and selfie captions — funny, aesthetic, savage, or wholesome

Conquer the 4 tonal contours of Mandarin Chinese (High Flat, Rising, Dipping, Falling) and explore foundational HSK 1 vocabulary with native Mandarin speech audio (`zh-CN`).

Generate perfectly formatted citations in APA, MLA, or Chicago style. Supports multiple authors, websites, and academic sources.

Interrogate any argument, news headline, debate talking point, or internal decision. TruthLens scans text against 24 universal cognitive biases and logical fallacies to sharpen your critical thinki...

Fix the most common English errors — its/it's, there/their, affect/effect and more — one sentence at a time.

PROFESSIONAL TOOL - Create tailored cover letters with industry-specific templates, ATS optimization, and professional tone analysis. Used by career coaches worldwide.

Prompts, character and plot generators, story ideas, world builder, word bank and focus timer for writers.

A blank page, a word goal and a streak you do not want to break. Write every day — 750 words is the classic target, but any goal works — and this counts the words, keeps your streak, shows you the ...

💼 Generate perfectly crafted professional emails, LinkedIn messages, and business communications. Includes tone analysis, etiquette tips, and productivity features.

Generate structured essay outlines, starter paragraphs, and writing guidance for any topic. Perfect for students, writers, and professionals!

Build your first CV or resume — even with no experience. Fill in what you have, get a clean, professional resume

Master the most critical French irregular verbs (être, avoir, aller, faire) and unlock fluent French pronunciation with our guide to silent consonants and natural liaisons.

Conquer the 4 German grammatical cases (Nominativ, Akkusativ, Dativ, Genitiv) and understand exactly how der, die, das shift based on subject, direct object, indirect recipient, or possession.

Competency questions ("Tell me about a time you dealt with conflict…") are won or lost on structure. Draft your Situation, Task, Action and Result below — with the 10/10/60/20 word split interviewe...

Drill the English verbs that refuse to follow the rules — go/went/gone, swim/swam/swum — in 8-question rounds, with a full reference table and your personal missed list. All local.

Conquer Japanese counter words (助数詞 - Josūshi). In Japanese, you cannot simply say "three beers" or "two cats"—objects require specific counters with euphonic sound shifts (rendaku).

Master the foundation of Japanese. Interactive 46-character syllabaries for both Hiragana and Katakana with native audio pronunciation, dakuten/handakuten sound changes, and a speed flashcard drill...

Learn, practice, and master Japanese kanji with REAL stroke order animations, meanings, readings, and example words.

Navigate the 3 crucial Japanese speech registers: Casual (with friends), Teineigo (everyday polite), Sonkeigo (honorific/clients), and Kenjougo (humble/self-lowering).

Master the grammatical glue of Japanese sentences (助詞 - Joshi). Practice tricky distinctions like は vs が (topic vs subject) and に vs で (time/target vs location of action) with interactive fill-in-t...

Instantly conjugate any Japanese verb across all core grammatical forms (Present, Negative, Past, Te-form, Potential, Volitional, and Passive) with group detection (Godan, Ichidan, Irregular).

Supercharge your Japanese vocabulary for the JLPT N5 and N4 examinations. Includes native audio pronunciation, Furigana reading toggles, English definitions, and contextual example sentences.

Paste copy and see word count, the densest terms, and an optional target keyword’s density. Counts are local and crude (no stemming). Density is a diagnostic, not a Google ranking lever — stuffing ...

Learn Hangul (한글), the world's most scientific writing system. Explore the 14 basic consonants, 10 vowels, and combine them into complete Korean syllable blocks with native audio pronunciation (`ko...

Translate words, check meanings, and practice languages. Uses open-source translation services.

Building a tabular by hand is the most reliably irritating ten minutes in academic writing: alignment letters to count, & and \\ to escape, and one unescaped % or _ to break the whole build. Paste ...

Estimate LLM token usage, calculate API cost per query, and compress prompt text to eliminate token waste and latency.

Generate filler text for mockups and layouts: classic Lorem Ipsum, plain English, or themed flavours (tech jargon, cooking, pirate, corporate, hip hop). Choose paragraphs, sentences or words, wrap ...

Transform raw Markdown into publication-ready corporate memos, academic whitepapers, and printable PDFs with 1-click browser export.

Write, preview, and format Markdown in real-time. Features instant HTML rendering, live word & reading time analytics, syntax quick-tags, and 1-click export to Markdown or HTML.

The ultimate internet language decoder. Translate memes, slang, acronyms, and internet speak with context, origins, and examples. 🌐 Real-time translation across internet cultures

Translate text to Morse code and back. Listen to the Morse code audio and learn the international standard.

Master the international radio alphabet — Alfa, Bravo, Charlie — used so letters can never be misheard. Spell words out loud, test yourself letter by letter, and see the pronunciation table. Runs e...

Spell a name, postcode or booking reference the way air-traffic and support desks do. ICAO/NATO alphabet (Alfa, Bravo…). Digits stay as words.

Name the eight parts of speech — noun, verb, adjective, adverb, pronoun, preposition, conjunction, interjection — in 10-question rounds with hints and a reference guide.

Copy text out of a PDF and you get a line break every few words, “docu- ment” split in two, fi and fl ligatures that break search, and page numbers and running headers in the middle of sentences. Pas...

Check text for originality and similarity with common phrases. Local processing only — no data sent online.

Count characters against the live limits for X/Twitter, SMS, Google titles, Instagram, LinkedIn and more. Everything stays in this box — no draft is uploaded.

Fit your talk to its slot: reserve time for questions and pauses, calculate a speaking word budget, then check your draft against it.

Advanced text analysis for grammar, style, readability, and clarity. Get detailed suggestions with explanations.

Improve your speeches with AI-powered analysis, practice tools, and personalized feedback. Practice timing, structure, delivery, and confidence.

Master the art of punctuation with this comprehensive guide. Learn rules, see examples, and test your knowledge. Perfect for writers, students, and professionals!

Analyze text readability with multiple scoring systems. Get actionable insights to improve your writing for any audience. Supports 8+ readability formulas with visual feedback!

Calculate precise reading time estimates with multiple input methods, audience presets, and detailed breakdowns. Perfect for writers, editors, and content creators!

One minute of form, one courteous letter. It works out your contractual last day, keeps the door open, and never says anything you’ll regret — fill it in and copy it out.

Find true rhymes and near rhymes for any word — powered by an embedded CMU pronunciation dictionary, no network needed.

Type in standard alphabet (Romaji) and watch it convert in real-time into Hiragana and Katakana. Also translates Kana back into Hepburn Romaji with 1-click text-to-speech audio pronunciation.

Advanced spelling checker using multiple open-source dictionary APIs combined for maximum accuracy. ⚠️ Requires internet connection for online dictionary checks.

Sharpen your reasoning: stress-test any claim with Socratic questions, steelman the other side of an argument, and learn to spot 10 classic logical fallacies with a quiz.

Master Spanish verb conjugations, conquer the notorious Ser vs Estar dilemma (permanent essence vs temporary state), and master Por vs Para with native Spanish audio playback.

Measure your words-per-minute, then train with guided pacing where your eye is told where to look. Includes recall questions and live WPM tracking. Nothing is stored online.

Train your brain to read faster with rapid serial visual presentation — while absorbing fascinating true passages about science and history. Includes a comprehension quiz so speed never beats under...

Roll story dice for a hero, a setting, a mysterious object and a plot twist — then write the tale. With challenge-mode constraints, story starters and saved prompts for classrooms and young writers.

Find better words — synonyms and near-synonyms for 100+ common English words, with usage tips for the tricky ones.

Convert typed text into realistic handwriting. Choose styles, sizes, and colors. Download as image.

Create images from text. Choose fonts, colors, backgrounds, and sizes. Perfect for social media posts and headers.

Paste any text and have your device read it aloud using the voices already built into your browser or operating system — no upload, no account. Choose voice and language, adjust speed and pitch, fo...

Split long text into a numbered thread that fits X, Bluesky, Mastodon or Threads limits, breaking at paragraphs and sentences rather than mid-word. Nothing is posted or uploaded.

Practise classic tongue twisters at your own pace, then beat the clock: read as many as you can in 30 seconds.

Translate text between languages with style and tone analysis. Includes language detection and clarity checking!

Measure your typing speed and accuracy with live feedback. Type the passage, watch your WPM build as you go, and see exactly which characters you missed. Your keystrokes never leave this page.

Build typing speed by retyping fascinating true mini-stories — bees, pyramids, photosynthesis. Live WPM, accuracy, tricky-key analysis and personal bests.

Add words with definitions and examples, practise with flashcards or quick quizzes, and track progress with simple Leitner boxes. Data is stored locally in this card.

Paste any text — an article, a meeting transcript, a speech, your own journal — and see what it is really about. Common filler words are stripped out, the survivors are sized by how often they appe...

Visualize 3D mathematical surfaces — rotate, zoom, and explore equations in real time.

“To get into my email I need a code sent to… my email.” Map what unlocks what, then simulate losing your phone, a house fire or a forgotten password. Finds circular recovery loops and single points...

How well are you really adulting? Take this brutally honest assessment and find out.

Create interactive timelines, explore historical databases, and visualize events across civilizations. Perfect for students, educators, and history enthusiasts!

Manage household chores, assign tasks, set schedules, and track completion with reminders. Perfect for families and shared living!

Advanced color manipulation with multiple effects, palette extraction, and real-time preview. Transform images with professional color tools!

Create scannable QR codes for URLs, text, Wi-Fi, contacts, email and SMS — custom colours, optional logo, batch ZIP. Everything is generated on your device; nothing you encode is sent anywhere.

Advanced timer with countdown, stopwatch, intervals, lap times, and multiple alarms. Perfect for workouts, cooking, study sessions, and productivity.

Generate beautiful color palettes for designs, social media, and vibes — click to copy hex codes

Turn vague thoughts into high-performance AI prompts used by senior prompt engineers. Constructs rigorous prompts with Chain-of-Thought reasoning, XML delimiters, output schemas, and anti-hallucina...

AI-powered team management with workload balancing, predictive analytics, and automated optimization. ⚡ Smart suggestions • 🎯 Predictive deadlines • 📊 Real-time analytics

Build your own custom AI tools by combining different AI capabilities. Create, save, and share personalized mini-tools in minutes! ✨ No coding required - drag, drop, and customize!

A column of dates from an export, a bank statement or a colleague abroad: is it DD/MM or MM/DD? Looking at one date can’t tell you, but the whole column can. This tests every format against all val...

Generate retro ASCII text banners and terminal art for code headers, GitHub READMEs, Discord bots, and CLI scripts.

The silence is deafening. Someone needs to say something. Let us help. (Results may make it worse.)

Validate or generate the check digit for EAN-13, UPC-A, EAN-8, ISBN-13, ISBN-10, GTIN-14 and ITF-14 barcodes. Shows the arithmetic so you can see exactly why a code passes or fails.

No birthdays added yet. Add your first birthday above!

Something went wrong? Don't worry — it's definitely not your fault. Let science* find someone else to blame. *Not science.

Convert UK, US, EU/FR and AU band + cup. Sister sizes keep the same cup volume (one band up, one cup down). Brands still vary — treat this as a starting letter, not a fitting.

Print sizes and pixels for UK/EU (85 × 55 mm), US (3.5 × 2 in), Japanese and Chinese cards. Add 3 mm bleed if a printer asks for it. Not a design studio — just the millimetres they keep getting wrong.

Type your suitcase in centimetres and see which common airlines it should fit, including wheels and handles as the airline measures them. Limits change — confirm on the carrier’s site before you fly.

Fill a jar with water, weigh it, and you’ve measured your candle. Enter vessel size and fragrance load — get wax grams, fragrance grams, wick guidance and a full batch shopping list.

Map out your career goals, milestones, and track progress over time. Save and manage multiple career plans.

Forge an entire fantasy world from a single seed. Tectonic uplift raises mountains, rain shadows carve deserts, rivers find the sea, and civilisations rise where the land is kind. Every kingdom, to...

Browse cat photos from free public APIs. Features infinite scrolling, favorites, and breed info.

Monitor Wikipedia blocks and Reddit content moderation in real-time. ⚠️ Educational tool - uses public APIs

Work out what a genuinely cheap fare looks like on your route, then jump straight into the right searches. Pick your airports, say when you want to travel and type the best price you have found: th...

Calculate molar mass, balance equations, analyze compounds, and reference periodic table data.

Design and generate beautiful, custom HTML Christmas cards in seconds. Perfect for emails, social media, or personal websites.

Count down to Christmas with real-time tracking, festive facts, and daily suggestions! 🎅 Shows days, hours, minutes until Christmas morning

Plan, track, and manage cleaning tasks with smart scheduling. Never forget a chore again!

Save and manage text snippets. Copy, pin, search, and organize your frequently used text. Persists in browser storage.

Upload a gameplay clip, pick a segment, and export a perfectly framed vertical short (9:16) or other preset. Adds caption safe zone and optional watermark.

Convert common adult clothing sizes between US, UK and EU for tops, dresses and men’s shirts. Charts are industry averages — cut, stretch and brand vanity sizing still win. Measure twice.

The daily sartorial gamble, solved. Dial in the temperature, wind and rain, tell it how long you'll be out, and it will tell you what to wear — with the correct level of weather-based sass.

Discover meaningful coincidences and synchronicities across multiple real-time data sources. Tracks news, numbers, dates, names, and global patterns!

Convert between HEX, RGB, HSL, HSV, CMYK, and OKLCH color spaces, generate color harmonies, test WCAG 2.1 contrast ratios, and copy CSS color code.

Turn a shared equipment list and borrowing requests into a conflict-checked lending schedule. Track which items are available, flag double bookings, and leave time for return and inspection.

Calculate commute time, cost, and environmental impact. Compare different transportation modes. ✅ Tracks daily, weekly, monthly, and yearly totals

Find missing items, overlaps and duplicates between two lists. Compare locally without uploading customer names, stock lists or other text.

Generate absurd conspiracy theories that are somehow more believable than the real ones.

Mark off buzzwords as your colleagues say them. First to get 5 in a row wins (and loses, because you're still in the meeting).

The antidote to impulse buying. Feed it a price and honest usage guesses, and it tells you whether that thing is a bargain, a luxury, or a future eBay listing.

Holidays, exams, releases, birthdays, notice periods or a deadline you are trying to respect: pick a date and watch the days, hours, minutes and seconds tick down live. Also tells you the working d...

35 mm-equivalent focal length = actual focal length × crop factor. Also shows equivalent f-number for depth of field (same framing). Field of view matches; light-gathering of the aperture does not ...

Generate cryptographic hashes (SHA-256, SHA-512, MD5), HMAC signatures, and multi-format encodings (Base64, Hex, URL). Fast, client-side, and zero-knowledge.

Design modern frosted glass (glassmorphism) components and mesh gradients. Real-time visual canvas with 1-click cross-browser CSS.

48 verified fascinating facts across space, nature, history, the body, Earth and technology — with a fact of the day, favourites and a quiz mode that turns trivia into knowledge.

Evaluate complex career, business, or lifestyle choices using weighted multi-criteria scoring. Removes emotional bias and highlights the winning tradeoff.

Advanced Pomodoro timer with productivity tracking, ambient sounds, and progress visualization. Stay focused, maximize productivity!

Carriers bill the higher of actual weight and volumetric (dimensional) weight. Enter the box and compare IATA /6000, DHL·FedEx /5000 and US domestic /139. Not a postage quote.

COMPLETE DOG VIEWER - Browse thousands of dog photos with breed information, favorites, and infinite scrolling. Multiple API sources for maximum reliability.

“Why is my weekly meeting suddenly an hour off?” Because the US, Europe, and much of the Southern Hemisphere change clocks on different dates. Enter a recurring meeting and the attendees’ cities to...

Set reminders for upcoming events with notifications, priorities, and recurrence options.

Seat guests at tables for a wedding, party or dinner: households stay together, people you name are kept apart, and friends are seated together where possible. Your list never leaves the browser.

📚 A comprehensive exam planning and study management system for students and professionals. Track exams, create study schedules, set goals, and manage revision.

Design chunky 3D logos: real perspective rotation (rendered slice-by-slice in software), adjustable extrusion depth, bevel light, backdrops and one-click PNG export. No WebGL, no libraries — just m...

Pattern envelopes quote fabric for one specific width, and most fabric is not sold in that width. This converts for the width you actually bought, then adds the three allowances people forget: a pa...

Verify file integrity and calculate cryptographic hashes. Compare hashes to verify file authenticity!

Enter the flat-pack battlefield armed with the truth: how many pieces, which tools, who's helping, and how many drinks deep you are. It will forecast your evening with alarming accuracy.

Generates a typographic scale where every size scales smoothly between two screen widths, using the CSS clamp() function — no media queries, no jump at a breakpoint, and no text that is 14px on a p...

Convert between UK MPG, US MPG, litres per 100 km, km per litre and miles per litre in one go — or calculate your real-world economy from a fill-up (miles driven and litres added). Includes a cost ...

Plan, track, and optimize your garden with planting schedules, care reminders, and plant databases. Grow your perfect garden!

Find the perfect gift with smart suggestions, reminders, and inspiration for every occasion.

A scientifically unserious instrument that measures how long it has been since you touched grass. Answer honestly, and it will tell you exactly how urgently you need to go outside — then give you a...

Set, track, and achieve your goals with progress monitoring, milestones, and motivational reminders.

40 inspiring quotes from history's greatest scientists, inventors and thinkers — each with context about who said it and why it matters. Search, filter by theme, save favourites.

Shared house, road trip, group holiday or a flat's running costs: log who paid what and who it was for, and this works out everyone's balance and the fewest transfers that settle the whole group. E...

Build consistent habits with visual streaks and daily tracking. Save your progress automatically!

Convert head circumference to UK, US and cm hat sizes. US size ≈ circumference in inches ÷ π. Measure just above the ears, level around the widest part. Felt hats often want a snug fit; straw can r...

Share recurring jobs fairly: rotate a weekly list of chores across housemates and generate a copyable multi-week rota.

The dating app for you and a plant. Answer honestly about your light, your watering habits and your pets, and it will set you up with a houseplant that can actually survive you.

Hyperfocal distance H = f² / (N × c) + f. Focus there and everything from H/2 to infinity is acceptably sharp. Circle of confusion defaults: full frame 0.030 mm, APS-C 0.019 mm, Micro Four Thirds 0...

Convert images to Base64 data URLs for inline CSS & HTML embedding, or decode Base64 strings back into downloadable images.

Decode QR codes instantly from uploaded screenshots, images, or your live camera feed. 100% private in-browser decoding — photos never leave your device.

Convert a date to its ISO-8601 week (YYYY-Www-d) and the other way around. Weeks start on Monday; week 1 is the week with 4 January (the week containing the first Thursday).

Format, validate, convert between JSON & YAML, and compare structural diffs side-by-side. 100% private in-browser processing.

Convert a calendar date to Julian Day Number (JDN) and Modified Julian Date (MJD = JD − 2,400,000.5). Astronomers count days from noon UTC on 1 January 4713 BCE. Gregorian calendar after 15 Oct 1582.

The four sums every knitter and crocheter does on the back of a pattern envelope: how many stitches to cast on at your gauge, how much yarn to buy, whether that leftover ball is enough, and which h...

The complete “how to actually do it” guide: pick a fabric and get the right water, cycle and drying, get a step-by-step recipe for any stain, and decode those cryptic care-label symbols in plain En...

Log laundry loads, track completion, and monitor laundry habits with statistics.

Gregorian leap years are divisible by 4, except centuries unless divisible by 400. 1900 was not a leap year; 2000 was. Also shows the weekday for any date your browser can represent.

Answer 8 quick questions to discover your preferred learning style: Visual, Auditory, Reading/Writing, or Kinaesthetic.

Work backwards from your arrival time to find when to start getting ready and when to leave, including travel and a safety buffer.

Perform matrix operations: addition, multiplication, determinant, inverse, transpose, and more. Supports up to 4x4 matrices with visual formatting.

Paste a list of numbers separated by commas, spaces, or new lines.

Turn topics and durations into an exact running order, including a break and a clear finish time.

Find optimal meeting times across multiple time zones, track availability, and generate meeting agendas. Perfect for remote teams, interviews, and collaborative scheduling!

Drop in any picture, add classic Impact captions or a modern white caption bar, and download a clean PNG. Text wraps and shrinks to fit automatically. The image never leaves your device and there i...

Your life, visualised as a grid of weeks — then converted into how many summers, books and Sunday roasts you have left. Not to scare you. To make the next one count.

Add items to memorize, then test yourself by revealing them later. Perfect for studying, learning vocabulary, or remembering important facts. 💡 Click items to hide/reveal • Drag to reorder • Expor...

Memorise anything with the 2,500-year-old method of loci used by memory champions. Build rooms, place vivid images at each stop, walk your palace, then test your recall.

A proper mind map in the browser: Tab for a child, Enter for a sibling, drag to rearrange, collapse branches you are not working on, and export as an image, a Markdown outline or a JSON file you ca...

Pop in your UK vehicle dates and see exactly how many days you have left, the earliest date you can take the MOT without losing time on your certificate, and a plain-English checklist to copy into ...

Build a volunteer coverage proposal that respects individual limits. Match availability to community shifts, prioritise hard-to-cover slots, and reveal staffing gaps rather than silently double-boo...

New shutter = old shutter × 2^(stops). ND8 is 3 stops, ND64 is 6, ND1000 is 10. Use it for silky water and daytime video at 180° shutter. Recheck highlights — filters are not perfectly even.

Most negotiations are lost in the ten minutes before them, in the negotiator’s head: no written walk-away, no BATNA, no plan for the first number. Fill in six fields and this produces the one-page ...

Convert numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36. Live conversion as you type.

Lightweight, private Kanban board with drag-and-drop cards, custom columns, priority tags, WIP counts, markdown export, and local storage auto-save.

Turn your screen into a ruler. Calibrate once with a bank card (85.6 mm wide) or by entering your screen's diagonal size, then measure real objects in mm, cm and inches — and convert between CSS pi...

A plain, fast notepad that saves itself as you type. Several notes in tabs, live word and character counts, find & replace, and one-click download as .txt — all stored in this browser, never on a s...

Work out how long a shift is when it crosses midnight, plus unpaid breaks and overtime after a threshold. Built for night staff, on-call rotas and timesheets — not a payroll system.

Time yourself reading a passage to measure your words-per-minute rate.

Convert between different baking pan sizes and adjust recipes. Calculates volume differences and ingredient scaling.

ISO A/B/C series, US Letter/Legal/Tabloid and pixels at print DPI. A4 is 210 × 297 mm; Letter is 8.5 × 11 in. Sizes are the ISO 216 trimmed sheet, not the printable area.

Compare actual and volumetric parcel weight, calculate length plus girth, and check against the limits on your chosen courier service.

Plan your party with date, location, and guest list.

Type what you actually want to say. We'll make it sound professional. Ish.

Official print sizes and pixel dimensions for UK, US, Schengen, Canada, Australia, India and China visa photos. Face-height rules are listed — a home print can still be rejected if lighting or back...

Create strong, random passwords instantly. Customize length and character sets.

Type a password to see its entropy in bits, estimated time to crack at online, offline and GPU-cluster speeds, and specific weaknesses — dictionary words, keyboard walks, dates, repeats and common ...

Work out percentages, increases, decreases, and discounts in seconds.

Calculate permutations (nPr) and combinations (nCr) — how many ways to arrange or select items.

Log pet care tasks like feeding, walking, or grooming.

Hilariously harmless revenge ideas for life's minor annoyances. All legal. All petty. All satisfying.

Before you sell something online or post a photo of your home: see whether the picture reveals where it was taken (GPS coordinates), when, and on which phone — then download a copy with that metada...

Generate creative playlist names for Spotify, Apple Music, and YouTube — match the vibe of your music

Level up your daily productivity with science-backed 25-minute focus intervals, audio finish chimes, streak tracking, and gamified XP rewards for completed sprints.

Track and analyze your practice sessions with detailed metrics and progress visualization. Set goals, track habits, and measure improvement.

Money is frozen time. Convert any price into how many hours (and minutes) of your actual working life it costs — after tax, before snacks. That latte is cheaper once you've seen it in minutes.

Break a whole number into its prime factors and see whether it is prime.

Convert pixel dimensions to print size at a chosen DPI, or the other way around. 300 DPI is typical photo-lab quality; 150 DPI is fine for posters viewed from a few feet.

Make your own graph paper, dot grid, ruled refill, manuscript paper, storyboard sheets, Cornell notes, week planners and wall calendars — sized for real paper, drawn on the device and downloaded as...

Scientifically* valid reasons why you should absolutely do that thing tomorrow instead. *Not scientifically valid.

Calculate and analyze your daily productivity with detailed insights and actionable recommendations. Track progress and optimize your workflow.

PROFESSIONAL CV CREATOR - Build ATS-optimized CVs with multiple templates, real-time preview, and export options. Used by career coaches worldwide.

Generate increasingly absurd excuses for any situation. From "plausible" to "they'll never believe you."

Calculate project timelines with buffer days, weekend exclusions, and milestone planning. Plan realistically and track progress.

Generate QR codes instantly — all processing happens in your browser. No data leaves your device. Supports URLs, text, WiFi, email, and more.

Create a multiple-choice quiz, then test yourself. Questions save to your browser.

Cryptographically random numbers in any range (with or without repeats), dice rolls in D&D notation like 3d6+2, coin flips, and a fair picker that draws a winner or shuffles a list of names. Nothin...

Paste a list of names and split it into fair random teams — by number of teams or people per team. Add an optional skill rating to balance sides, pick captains, and copy the result to the group chat.

Perfectly scale any recipe with smart parsing, automatic unit conversions, and kitchen-tested measurements.

Create reminders that stay saved in your browser. Works offline — data saved locally.

Calculate a calendar-day deadline from a purchase or delivery date and the retailer’s stated return period, with an optional posting buffer.

Convert UK letters, US numbers, EU/ISO circumference and inner diameter. Based on a circular inside; wide bands often need a half-size up. Measure a well-fitting ring, not a string if you can help it.

A working library of the short, memorable rules people use to make decisions without doing the maths: how long money takes to double, how to season a sauce, how many copies a backup needs, how far ...

Track Santa's journey and send him a message! Get a personalized response from the North Pole. Perfect for kids and kids-at-heart!

Take this scientific* holiday quiz to discover if you're getting coal or presents this Christmas! *Not actually scientific

Short-stay visitors can spend 90 days in any rolling 180-day window in the Schengen area (unless a visa or residence permit says otherwise). Add trips; days of entry and exit both count. Not immigr...

Pixels per inch from diagonal size and resolution. Also shows pixel pitch, aspect ratio and whether the display is “Retina” at a typical viewing distance (1 arc-minute).

Organize a perfect Secret Santa gift exchange with automatic matching, restrictions, and wish lists! ✅ Supports: Family restrictions, wish lists, budget tracking, email notifications

Mask common identifiers before sharing a message, support log, or document. Detects likely email addresses, phone numbers, IPv4 addresses and Luhn-valid payment-card numbers; add exact phrases of y...

Convert adult shoe sizes between US, UK, EU and Mondopoint (mm). Based on standard last-length charts — brands still vary by a half size, so treat this as a starting point, not a fitting.

Create beautiful, interactive flashcards for effective studying. Supports rich text, categories, and spaced repetition.

Plan, track, and grow your perfect garden with AI-powered suggestions and smart scheduling.

Create intelligent packing lists with categories, trip types, weather considerations, and shareable checklists. Never forget an essential item!

Create custom quizzes, track progress, and test your knowledge. Perfect for studying, training, or self-assessment. Add multiple choice, true/false, or open-ended questions!

Add items, organize by category, track quantities, and manage your shopping efficiently. ✅ Features: Categories, quantity tracking, budget calculator, shareable lists

Create perfectly sized Open Graph and Twitter preview images with custom branding, layouts, and auto-generated HTML meta tags.

Type names, dinner options or chores one per line, spin, and let the wheel decide. Remove each winner as you go to draw a whole order. Your list is remembered on this device and nothing is sent any...

Advanced sprite sheet cutter for game developers. Slice, preview, animate, and export sprite sheets with professional tools. ✨ Supports PNG, JPG, GIF, and WebP formats

Stopwatch with lap splits, countdown timer, and interval beeps — all offline, no install. Great for workouts, cooking, presentations, and lab timing.

Plan your study sessions, track progress, and stay focused with a built-in Pomodoro timer. All data saved locally in your browser.

Focus timer with study/break cycles, session tracking, and motivational quotes — ace your exams

Inspect, edit, and optimize SVG path data (d="...") in real time. Visualizes anchor nodes, control handles, bounding box, and minified code.

Use the Eisenhower Matrix to prioritize tasks by urgency and importance. Based on the time management framework.

Comprehensive text analysis: word count, character count, sentence count, reading time, readability score, and more.

All 118 elements as numbered museum exhibits: discovery year, discoverers, name origin, category, state at room temperature — plus curator's notes on two dozen showpieces and an honest word where d...

Calculate exactly how many ways a situation can go wrong. Spoiler: it's more than you think.

Naming things is one of the two hard problems in computer science (along with cache invalidation and off-by-one errors). Point it at a thing and it will name it — band, pet, D&D character, startup,...

Play Tic Tac Toe against the computer or a friend. Features three difficulty levels and game statistics. Classic strategy game reimagined.

Add up a list of times like 1:30 + 2h45m, find the hours and minutes between two clock times (overnight shifts included), add a duration to a start time, and convert decimal hours to h:mm or 24-hou...

Convert any date and time between time zones. Supports all major world time zones.

Shots needed = clip length × frame rate. Real time covered = shots × interval. Leave the battery and a bigger card than you think. Sunset clouds often want 2–5 s; construction days want 30–60 s.

Type a task, press Enter, tick it off. Priorities, due dates with overdue warnings, reorder, filter and search — and the list is still there tomorrow because it is saved in this browser. No account...

Plan your perfect trip with detailed itineraries, budget tracking, and smart recommendations. Get personalized suggestions based on your preferences!

Compare two metric tyre sizes (e.g. 225/45R17 vs 235/40R18): overall diameter, circumference, sidewall and the speedometer error if you swap them. Not a load or speed-rating check.

Uppercase, insert the inward-code space, and check the Royal Mail pattern (e.g. LU1 2AB, EC1A 1BB, W1A 0AX). This is a format check only — it does not look up addresses.

Complete moving organization tool: Create checklists, track inventory, manage budget, schedule tasks, and coordinate with family/friends. Make your move stress-free!

Generate perfectly sized thumbnails for any platform with advanced editing tools. No upload required - all processing happens locally.

Generate unique, cool usernames for gaming, social media, and streaming — check availability vibes

The generational emoji gap, decoded. Search or tap an emoji to see what it really means, how your boss probably reads it, and whether it's safe for the work chat. You will never send 🙏 in the grou...

Can't decide what to watch? Answer 3 quick questions and get personalized movie/show recommendations

Discover your internet personality era based on your tastes, habits, and vibes. ← Share your result!

Generate an instant, scannable QR code for your home, studio, or office Wi-Fi network. Guests can scan with their phone camera to connect immediately without typing complicated passwords. 🔒 Genuin...

Caffeine has a half-life of roughly five hours, which is why the 4pm espresso is still in your system at midnight. Log what you drank and when, and find out how much will still be circulating at be...

Calculate work hours, breaks, overtime, and pay. Track multiple shifts, different pay rates, and generate detailed timesheets. Perfect for freelancers, contractors, and employees!

A live board of any cities you care about: local time, weekday, date and real UTC offset with daylight saving already applied. Add up to twelve, drag the hour slider to see what one moment looks li...

Find a meeting slot that works across cities. Add up to eight time zones, drag the slider through the day and see each city's local time colour-coded as working hours, early/late, or asleep. Daylig...

Struggling with what to write? Get personalized Christmas card messages for everyone on your list! Save time, spread joy!

Grow or crop a rectangle to φ ≈ 1.618, place a golden-section grid, and convert any length into its complementary pair. Used by photographers and layout designers. Pure geometry — no image upload.

Convert between Linden Dollars (L$) and real-world currencies — USD, GBP, EUR, JPY, AUD, CAD

Convert Linden Dollars (Second Life virtual currency) to real-world currencies using market rates. Rates are estimates — actual exchange rates may vary.

🟢 LIVE Real-time events from Second Life. Updates automatically.

Generate ready-to-use Linden Scripting Language scripts — security, teleport, dance, auto-response, and more

Real tumbling 3D dice — D4 through D20 — rendered as true platonic solids. The die physically rotates so your rolled face lands front-and-centre. Includes roll history, fairness stats and a 100-rol...

A Wolfenstein-style 3D dungeon in pure maths — no game engine. Procedurally generated maze, glowing orb collectibles, a portal exit, minimap and touch controls. Click the view, then use WASD or arr...

Professional toolkit for Second Life builders: prim allowance, object sizing, weight calculation, grid alignment, and LOD optimization. ✅ Features: Prim/LI calculation, mesh optimization, physics a...

Search and browse Second Life Marketplace items. Demo data shown — in production, connect to actual Marketplace API.

View Second Life region maps with interactive pan/zoom, coordinates, and debugging tools. Uses multiple data sources with automatic fallback.

Explore the rich tapestry of Second Life surnames. Discover origins, cultural associations, and roleplay inspiration. A living encyclopedia with search, filters, and favorite tracking.

Calculate texture repeats, offsets, and rotations for Second Life prims. Perfect alignment for builders and creators. Works with any texture and prim size. This site is supported by user contributi...

Calculate your avatar's true height, body proportions, and get recommendations for realistic or stylized looks

Track your group memberships — manage the 42-group limit and plan which groups to keep or drop

Calculate monthly tier costs, prim budgets, and land area — for mainland, private regions, and homesteads

Estimate Land Impact and upload cost for mesh objects — input triangle counts and physics shapes

Plan and organize your Second Life outfits — track body parts, clothing layers, accessories, and color coordination

Plan your land's prim usage — add objects, track LI (Land Impact), and stay within your budget

Build teleport notecards, generate SLURLs, and plan region visits with coordinate calculations

Calculate upload costs, memory usage, and get recommendations for optimal texture sizes in Second Life

Convert between Second Life Time (SLT/PST) and your local time — never miss an event again

Generate a SLURL to meet Supadupaman Sapphire and configure the Arena visitor bot. Works with SupaViewer public map (no login) or a real bot account.

Review an audio clip locally: scrub, slow playback, loop a short A/B section, and bookmark exact timecodes for later listening. Your selected file is never uploaded or saved by this tool.

A recordable, full-screen-style radar graphic for a staged horror segment. Choose how many synthetic contacts appear and how quickly the sweep moves; save a still or capture your screen using your ...

Make a gentle, continuous horror sound bed from synthesized wind-like noise and low tones. Pick a room, mix the layers, and start or stop it yourself—no recordings or sound files are used.

Build a still-frame look for a horror video: green night-vision-style grading, heat-map colors, noir or analog-tape texture, optional grain and an optional orb overlay. Import and export stay on th...

Run a calm, predictable cue list for a permissioned horror shoot: room tone, camera holds, cast lines and resets. The tool only displays crew prompts—no lights, speakers, or devices are triggered.

If your browser exposes a magnetometer, read the phone's real magnetic field in microteslas, set a baseline, and mark changes with time. Unsupported devices stay honestly blank—no simulated readings.

A hard-stop preflight for spooky video shoots. It is designed for a controlled set, booked attraction or explicitly permitted property—not abandoned, closed or restricted buildings. No address or l...

A screen-friendly letter board that spells one prewritten horror line at a time. Choose the mood and reveal pace; use it as a fictional prop for a consenting cast on a controlled set.

Place an adjustable skeletal-tracking effect over a still photo for a clearly staged horror shot. Drag it into position with the controls, preview the framing, then export a PNG—no live camera or t...

A controllable, fictional word stream for horror shoots: pick a tone, set the pace, and optionally add a very soft synthesized static bed. No microphone, sensors, radio scanning, or network access.

Match a couple Halloween costume in seconds: pick a vibe, effort and budget, and get paired ideas with what each person wears and the build time.

Size the haze for a room: how long the machine takes to reach a target visibility, how often to re-burst, how much fluid an evening eats, and when the air clears again.

Plan a group Halloween costume that works for your headcount: matched themes, a role for every person, per-person costs and a group build schedule.

Buy the right amount of sweets: estimate the door traffic from your street, allow for the late rush, and see exactly when the bowl runs out.

Halloween costume ideas in seconds: pick who it is for, the vibe and the budget, and get three complete costumes with everything you need.

Will that costume survive the evening? Add the forecast, the wind and the layers underneath, and get an honest read on comfort, exposed skin and rain before anyone leaves the house.

Add up every prop on the circuit, check the breaker and the extension lead, and see what the display costs to run each night.

Plan Halloween face paint: pick a design, skin tone and time budget, and get the colours, steps, drying time and enough paint for the group.

Plan a Halloween movie marathon that ends on time: pick the start, the hours and who is watching, and get a running order with runtimes and breaks.

Turn your own name into a Halloween name: pick a style and a spookiness, and get three witch, vampire, ghost or monster names with a backstory.

Compare how far a driver can see a child with how far the car needs to stop — then find the reflective area that closes the gap.

Fill a Halloween party with games that fit the age group, room and time — with durations, supplies and a running order that works.

Build a Halloween party playlist that fits the night: pick the hours, the guests and the energy curve, and get a timed song list block by block.

Generate a printable Halloween scavenger hunt: choose the age, the area and the number of clues, and get riddle cards, a route and an answer key.

Generate Halloween trivia questions and answers for a party quiz — rounds, difficulty, teams, a printable score sheet and a tiebreaker.

Find the scene that sets the pace, work out how many groups an hour the attraction can pass, and see the queue that builds when arrivals outrun it.

Plan the carve before the knife goes in: how long the pattern will take, how many candles it needs, how much air the flame gets, and what to check before you light it.

A last-minute Halloween costume from what you already own: pick the minutes and the clothes you have, and get a costume with no shopping trip.

Turn a whole pumpkin into a known quantity of purée, see how many pies it will fill, and scale every ingredient — including how many pumpkins to buy.

Free pumpkin stencil generator: choose a face, size and difficulty, and get a printable pattern with cut order and bridge widths.

Build a campfire story from a promise, a rule, a mistake and a twist — five beats that hold together, at a scare level you choose. Every word is generated here; nothing is fetched.

Work out how long the rounds actually take: distance, doors, walking and doorbell time, whether you finish before dark, and how much sweets each child comes home with.

Review ordinary, testable possibilities for a specific observation before drawing conclusions. Each status and note is investigator-entered; the tool does not rank explanations or label anything pa...

Capture an independent first-pass transcription before revealing the question or expected phrase. Then replay, record a second pass and compare the notes without the tool supplying words.

Compare manually recorded baseline readings with a later observation at the same marked point. Use calibrated instruments, note their position, and report the raw difference instead of calling a ch...

Record a pre/post-session check against a known reference for each instrument. Enter the manufacturer’s stated tolerance yourself; this page does not invent calibration limits or certify a device.

Create a local inventory of selected evidence files with file metadata and SHA-256 hashes for manageable files, then append handling events. This helps detect later file changes; it does not prove ...

Pre-register a small A/B field test before you start: define the question, conditions, repetition count and scoring rule, then generate a balanced random order. This helps separate an observation f...

Keep a neutral, timestamped field log while a permitted investigation is underway. The clock is manual; observations are written by your team, not inferred from sensors.

Capture a witness’s account in their own words, then record context separately. Use open prompts, interview witnesses individually, and avoid suggesting a sound, figure, or cause.

Make a simple, address-free room grid for a permitted site. Plot observer positions, instruments, control points, measurements or no-go hazards so a team can describe where a note came from.

Build a clear field report that separates direct observations from interpretations, records methods and limitations, and includes permission and ordinary-explanation checks. Nothing is saved or sen...

Test your knowledge of ancient Egypt — pharaohs, pyramids, gods and everyday life — in ten-question rounds with streaks.

Name the kings and queens of England, Scotland and the UK from 1066 to today — ten questions per round with streaks.

Walk 4.6 billion years of Earth's story in one scroll — Hadean to Holocene, an era per hall, with an Earth-in-one-day clock, jump-chips and a catalogue-numbered plaque for every exhibit...

Conditional probability you can feel: what a positive test really means (Bayes' theorem), a 300-game Monty Hall simulation, and the prosecutor's fallacy — with a 10,000-person grid painted live by ...

A teaching coat, not a grant. Choose a field, an ordinary and a charge. The plaque writes the blazon in the old word-order: metal or colour first, then the ordinary, then what stands upon it. Rule ...

Early Imperial bronze and silver, counted in asses. 4 asses = 1 sestertius; 4 sestertii = 1 denarius; 25 denarii = 1 aureus. A legionary under Augustus took 225 denarii a year (before stoppages). E...

The constants that run the universe, as numbered exhibits — provenance, exact or measured, and what each does. Includes a live pi engine (Machin's formula computed with big integers), a golden-rati...

Watch sunlight enter a room and cast shadows as the sun moves across the sky. See how window orientation, room depth, and time of year affect daylight levels. The sun path diagram shows the sun's a...

Melvil Dewey, 1876: knowledge in ten main classes, each split by tens. Museums and small libraries still live by it. Search a word or tap a hall. This is the public summary, not a licensed DDC sche...

Watch sound bounce around a room in real time. See wavefronts propagate from a source, reflect off walls, and decay as materials absorb their energy. Adjust room size, wall material, and source pos...

British silver and gold are punched with a standard, a town, a maker, and (historically) a date letter. The bench identifies the town mark and the millesimal fineness. Date letters cycle by assay o...

Not a ladder. A bush of species, several of which overlapped. Brain volumes are typical adult means; dates are first-to-last fossil appearances as currently argued. The corridor will not tell you w...

Three statistical traps you can run with your own eyes: survivorship bias (the WW2 planes), Simpson's paradox (the kidney-stone study where one treatment wins overall yet loses everywhere), and reg...

Romans counted forward to the next named day, inclusively. The named days are the Kalends (1st), the Nones (5th, or 7th in Mar/May/Jul/Oct) and the Ides (13th, or 15th in those four months). The Id...

Friedrich Mohs, 1812: a mineral of higher number scratches one of lower number. The steps are not equal — corundum to diamond is a canyon. Pick two specimens (or a thumbnail and a steel file) and t...

Watch water migrate through building materials via capillary action — the same force that makes a sponge soak up water and makes your walls draw moisture from the ground. See why rising damp happen...

Japanese objects are dated in era years: Meiji 6, Shōwa 20, Reiwa 6. Year 1 of an era is the year it was proclaimed, even if that was December. The desk covers Meiji (1868) to Reiwa. Earlier nengō ...

Vitruvius counted in modules: the lower diameter of the column. Doric is stocky, Corinthian tall and leafy, Ionic the volute in between. Enter a diameter in metres; the plaque returns shaft, capita...

Colour as a dated substance. Each pot is a first-use, a chemistry, and a verdict: still on the palette, replaced, or locked in the poison cupboard. Swatches are screen approximations — never a spec...

Watch water flow through pipes in real time. See Bernoulli's principle in action — where the pipe narrows, water speeds up and pressure drops. Particles show laminar vs turbulent flow. Adjust diame...

English and British legal years used to be counted from the accession, not 1 January. “3 Geo. III” is the third year of George III’s reign. The desk covers the Hanoverians to the present, plus a Tu...

Lengths and masses as the casts in the hall give them — mid-range figures from the current literature, not movie posters. Enter your height; the gold line is you, standing at the snout.

A Hellenistic tourist list, not a league table. Antipater of Sidon and others named seven sights a traveller from the Mediterranean might still catch. Only the Great Pyramid is still standing. The ...

Apply loads to a beam and watch stress propagate in real time. See shear force and bending moment diagrams update live. The colour map shows where failure begins — red zones are where your shelf, j...

Watch heat flow through building materials in real time. A thermal wave propagates from a warm room through brick, insulation, glass or wood — Fourier's law made visible. See why a 100mm air gap is...

The quiet rectangle beside the object. In Anglo-American practice: maker, dates, title in italics, date of work, medium, dimensions, credit line, accession number. Fill the fields; the wall card se...

Energy literacy in the only currency that needs no conversion: bananas, stairs and phone charges. Decode any item, your monthly meter, and the kinetic energy of a moving car (E = ½mv²).

Sixteen staves, not twenty-four. After about 700 CE the north dropped Elder Futhark down to this tighter case — one rune now stands for several Latin letters. Stones from Jelling to Rök speak it. T...

The twenty-four single-consonant signs every student copies first — Gardiner’s teaching alphabet. Vowels were not written. Type a name; the case sets the glyphs and the catalogue codes. This is not...

Type in the scale ticket. This checks every axle group and the federal bridge formula, then tells you which way to slide the fifth wheel or the tandems and how far — in inches and in holes — based ...

What a mile actually costs you to run — fixed costs spread over the miles you really do, plus fuel, tyres, maintenance and driver pay — and the rate per mile that leaves a profit rather than a stor...

How much driving have you actually got left, when is your break due, and what time does your day end? Pick your rule set, drop in the numbers from your log, and this shows every limit counting down...

What a grade actually means in degrees and feet, how fast your truck can hold it, and — the part that ends careers — how much heat a descent puts into your brakes, whether your retarder can carry i...

Three offers on the table, one honest answer. Puts the deadhead into the rate, subtracts what the truck costs to run, turns it into money per hour, and tells you the exact number to ask for if the ...

A walkaround that follows the order you actually walk: paperwork, engine, cab and air brake tests, lights, tyres and brakes, coupling and trailer, securement. Tick what passes, flag what does not, ...

Something has gone wrong at the worst possible place. Pick the symptom and this walks you through what is safe to check, what each finding most likely means, whether you can carry on or stop, and e...

Where your truck actually stops — thinking, brake lag and rubber on the road, added up — and the following gap in seconds that goes with it. Change the surface, the grade or the load and watch the ...

How many pallets fit, which way round, where the weight ends up on the axles, and what order to load them so the first drop is at the doors. Draws the floor plan as you type, offline, for a 53’ van...

Three checks a driver actually does: is this axle over its tyres' rating, is the pressure rise on the road normal or is something dragging, and do the tyres on a set of duals match closely enough t...

Work out deemed service under CPR 6.14 and 6.26, then the acknowledgment, defence and reply deadlines, claim form validity and the CPR 2.8 court-office rule.

Estimate an unfair dismissal award: the age-banded basic award against the £751 week's pay cap, the capped compensatory award, ACAS Code uplifts and the Vento bands.

Estimate Inheritance Tax on an estate: nil-rate and residence bands with the £2m taper, spouse and charity exemptions, business and agricultural relief, failed gifts and probate fees.

Find the last date to bring a claim in England and Wales — contract, tort, personal injury, land, defamation, human rights and employment tribunal deadlines, with the ACAS pause.

Work out court fees for issuing a claim, the hearing fee by track, applications, appeals, enforcement, assessment and probate — current EX50 fees, uplifted 13 July 2026.

Lift, theoretical and dependable lift at your elevation, the intake pressure correction, net pump discharge pressure, and how much of your rated capacity you actually keep at that lift.

Wet-bulb globe temperature from your three thermometer readings, the ACGIH screening TLV and action limit for your work/rest cycle, and why the tables stop short of turnout gear.

Friction loss, elevation, appliance loss, pump discharge pressure, solid-stream flow and nozzle reaction for up to five hose sections, with the supply-line hand methods alongside.

Foam solution flow for an area, concentrate per minute and total concentrate for the run time, for Class A and Class B hydrocarbon and polar-solvent spills.

Quarter rule, climbing angle from where the butt actually sits, the height a given ladder reaches, the ladder you need for a given objective, and the collapse zone for the building.

ppm to mg/m³ and back at the temperature and pressure you are actually working at, ppm to percent by volume, percent LEL to ppm, and what an oxygen reading means.

Read your pitot gauge and your two hydrant gauges, and get the percentage method, the first-digit method, the available fire flow at 20 psi residual, and whether the test is even valid.

Needed fire flow by the National Fire Academy, Iowa State and ISO methods side by side, with exposure charges and a hoseline plan for the answer.

Rule of thirds, EOSTI activation pressure, the actual duration your cylinder will last at a real consumption rate, and how long your air has been going based on how much you have used.

How many gallons per minute a water tender shuttle can actually put on the fire — NFPA 1142 cycle time, the 10 % unusable capacity allowance, and how many tenders you need for the flow you want.