BPM, tempo, and time signature — a 3-minute primer for the rest of us

BPM (beats per minute)

A number that tells you how many beats fit in a minute. 60 BPM = one beat per second. 120 BPM = two beats per second. 90 BPM is a slow walk; 140 BPM is house music; 60 BPM is a heartbeat at rest. The free BPM tapper on this site works out the BPM of any song by tapping along — you tap, it counts, it gives you the number.

Tempo markings

Classical music uses Italian tempo markings instead of numbers. Largo is very slow (40–60 BPM). Adagio is slow (66–76). Andante is walking pace (76–108). Moderato is moderate (108–120). Allegro is fast (120–156). Presto is very fast (168–200). Prestissimo is as fast as you can play (200+). The two systems coexist: a piece marked "Allegro" might be exactly 132 BPM, or it might be "feel like 132 BPM".

Time signatures

The fraction at the start of a piece of music. The top number tells you how many beats are in a bar; the bottom number tells you which note value gets one beat. 4/4 (four quarter notes per bar) is the most common — it is so common it is called "common time". 3/4 (three quarter notes per bar) is waltz time. 6/8 (six eighth notes per bar) is jig time. 5/4 is odd time and the basis of "Take Five".

Key and tuning

The key tells you which notes are in the piece. A is the most common tuning reference; an orchestra tunes to A = 440 Hz by default. The free tuner on this site listens to your instrument and tells you whether each note is sharp, flat, or in tune. The free BPM tapper tells you the tempo. The free chord builder tells you which notes are in a chord so you can play one. None of them require you to read music.

What this site gives you

A BPM tapper, a tuner, a metronome, a chord builder, and a scale visualiser. All free, all in your browser, none of them upload your audio anywhere. The BPM tapper uses the Web Audio API to listen to your microphone; the rest are visual or input-based and never touch your mic.