BPM finder

A catchy rhythm is not the pulse

The pulse has to be even. A stomp-stomp-clap pattern is a rhythm laid on top of that pulse. If you tap the clap, or if an onset detector follows the clap, you can print a multiple of the beat you will actually count. Nod or tap an even stream first, then check whether the printed number follows that stream or the fill.

70 and 140 can both be right; this page still prints one

The same recording at 70 BPM and at 140 BPM can sound identical. What changes is the grid: a snare on beat 3 in the faster count is the snare on beat 2 in the slower count, and an eight-bar loop at 140 is a four-bar loop at 70. Hi-hat rolls sit on a denser grid in the faster count, which is why the same groove feels easier to program in one number than the other.

This finder searches repeating onset intervals between 45 and 210 BPM and scores a mild preference for pulses near 115 BPM when half and double both fit. Those bounds and that preference are in the analysis code, not a claim about which grid is musically correct. If the printed number feels twice as busy or twice as slack as the kick you feel, use Half or Double and listen again.

6/8 and 3/4 get sliced as if they were 4/4

Six eighth notes fit in a bar of 3/4 and in a bar of 6/8. The difference is grouping. 3/4 has three strong beats, each splitting in two; 6/8 has two strong beats, each splitting in three. At a slow 6/8 the ear can latch onto the eighths and hear three; at a fast 3/4 it can latch onto two swinging beats instead.

This page does not read a time signature. It looks for a repeating onset interval. Inference from that design: a 6/8 groove can print the dotted-quarter pulse, the eighth-note stream, or a 4/4-shaped compromise that matches neither count you would conduct. If the music sways in two and the number only makes sense in four, keep the two-feel and ignore the print.

A drumless intro is a bad place to start the clock

There is still a pulse when there are no drums — long notes have silent subdivisions — but this finder measures attacks. A pad, a vocal pickup, or a bridge without kicks gives it little to lock onto, so it may return Unclear or follow melody onsets that are not the beat. Export the verse or chorus that actually has a grid, or wait until the drums enter.

Live takes and chased clicks will not sit still

If sections of the file disagree on the pulse, this finder returns Unclear rather than averaging them into one fake BPM. That is the right answer for a ritardando, a sped-up last chorus, or a live take that breathes. Map those sections in an editor instead of copying one number.

Matching a metronome by ear is a chase. It can take several bars to lock in, and the number can wobble while you do. If you then keep turning the click to follow a live recording, you are measuring the take’s drift, not a single tempo. Stop, pick a steady passage, lock one click, and listen for whether the music walks away from it.