Help & Contact

Genuinely free. All 1165 tools, no sign-up, no account, no trial, no paywall, no premium tier. There is no catch and no plan to add one. The site is hosted free on GitHub Pages, so it costs almost nothing to run. Donations are welcome but change nothing about what you can access.

No. There is no login anywhere on the site, so there is nothing to register for and no password to forget.

Yes. Use them for anything lawful, personal or commercial, with no licence fee and no attribution required. The site's code is MIT licensed — see the IP section. The MrProphecy music and artwork are not covered by that licence.

Yes. Open any tool and press the Embed button in its footer to copy an iframe snippet you can paste straight into your page.

Once a tool has loaded it runs entirely in your browser, so it keeps working if your connection drops. The catalogue index itself needs one initial load to fetch the tool list.

Please report it. Email hello@themostusefulsiteintheworld.com with the tool name, what you entered, what it returned and what you expected. Calculation errors are treated as urgent and usually fixed within a day or two.

Yes, and suggestions are where a lot of these came from. Email the address above with what the tool should do and what problem it solves for you. No promises on timing.

Partly — here's the honest answer. The site loads Google Analytics, which sets third-party cookies and counts visits in aggregate. That's how I can tell which of the 1165 tools people actually use and price sponsorship without guessing. It runs with IP anonymisation on and ad personalisation off, and there is no advertising network anywhere on the site.

What is never collected: anything you type into a tool. Those inputs are processed on your device and never transmitted. To opt out, use Google's opt-out add-on or any content blocker — the site works perfectly with analytics blocked. Full detail in the privacy section.

Nowhere. Every tool runs inside your browser. There is no server and no database behind this site, so your inputs are processed on your own device and never transmitted to anyone.

On your device, in your browser's localStorage. It never leaves your machine and only this site in that browser can read it. Clear your browser's site data to erase it completely.

Treat every result as an estimate, not professional advice. Health tools are not medical advice, finance tools are not regulated financial advice, electrical tools are sizing aids that a qualified person must sign off, and document generators are drafts, not legal advice. Check anything that matters with a qualified professional — see the full disclaimer.

Free on YouTube, on SoundCloud, or right here on the listen page. Nothing is gated and nothing is paywalled.

Start with the press kit for bio and discography, then email hello@themostusefulsiteintheworld.com with dates, location and what you have in mind.

Ask first — the music is all rights reserved, unlike the site code. Email what you want to use and where it will appear. Non-commercial use is usually fine; commercial or sync use needs a written agreement.

Donations are voluntary gifts toward development time. They unlock nothing — no exclusive tools, no early access, no ad removal, because there are no ads and everything is already free. Hosting is free on GitHub Pages, so nobody is claiming your money keeps the servers on. See the donations section.

Yes. Email within 30 days and it will be refunded, no argument.

See the sponsorship page. Placements are always labelled, never disguised as a recommendation, and sponsors receive no visitor data because none is collected.

Email the address below with the page URL, what the material is, what right you hold and your contact details. Valid complaints are acted on promptly and material comes down while it's reviewed. Full process in the takedown section.

No. It is an unofficial, non-commercial fan project with no affiliation to or endorsement by SEGA. Sonic the Hedgehog and all related marks belong to SEGA.