How to find the BPM of a song
- Drop a song or audio file onto the box: MP3, WAV, M4A, AAC, OGG or FLAC.
- The tempo appears in a few seconds, with a confidence note and a graph of the beats.
- Press Play with click to hear a metronome over the track and check that it lines up.
- If the number feels twice as fast or slow as the music, use ½ × or 2 ×. Many songs can be counted either way.
How BPM detection works
The analyser looks at the first two minutes of the track and measures how quickly the loudness rises, about a hundred times a second, which makes drum hits and note attacks stand out as peaks. It then compares this pattern with time-shifted copies of itself (autocorrelation): the shift at which the peaks line up best is the time between beats. A small preference for the 80–160 BPM range, where most songs are counted, helps choose between half and double time, and the result is refined to a tenth of a BPM.
DJs use the tempo to plan mixes and set pitch, producers to match samples and set their project tempo, runners and fitness instructors to build playlists at a target cadence, and dancers and choreographers to pick music. Songs with a steady drum beat give the most reliable results; rubato classical music, ambient tracks and songs that change tempo give an average or a less certain reading. For those, tap along with the tap tempo tool instead. Your files are decoded and analysed locally and never uploaded.
How accurate is the BPM detector?
For music with a steady beat, usually within 1 BPM. It may report half or double the tempo you count; use the ½ × and 2 × buttons.
Can it detect tempo changes?
It reports the main tempo of the first two minutes. Songs that speed up or slow down get an average.
Which file types work?
Anything your browser can play: MP3, WAV, M4A/AAC, OGG and usually FLAC.
Is my music uploaded?
No. The audio is decoded and analysed on your device.