How tempo detection works
Most music has a steady pulse: drums, bass notes and chords start at regular moments. The BPM finder looks for these moments, called onsets, by tracking sudden increases in energy across the frequency range. It then searches for the time interval that repeats most often between onsets. That interval, converted to beats per minute, is the tempo. Because a rhythm can also fit half or double that interval, the tool shows several candidates with the most likely one first.
The analysis runs in your browser. Your music file is not uploaded, and you can analyse full songs or long DJ mixes.
Why you see more than one result
Tempo is partly a matter of perception. A hip-hop track at 90 BPM can also be felt at 180 BPM if you count the hi-hats, and a drum and bass track at 174 BPM is often felt at 87. Both values are mathematically valid. The candidates help you choose:
- For DJ mixing, use the value that matches other tracks in the same style. House is around 120–128, drum and bass around 170–175.
- For practice with a metronome, use the value where one click equals one beat that you tap your foot to.
- For video editing, either value works; choose the one that makes cuts land where you want them.
The beat grid
After detection, the tool draws a grid of beat lines over the waveform, aligned to the first strong beat. Turn on the click track and play: if every click lands on a drum hit, the tempo and grid are right. If the clicks slowly drift away from the music, the song may have a slightly different tempo, or it was played live without a click and the tempo changes over time.
When detection is difficult
- Music without drums, such as solo piano, classical or ambient music, has fewer clear onsets. Results may be less certain.
- Live recordings and older songs often speed up and slow down slightly. The tool gives an average tempo.
- Songs with tempo changes have more than one tempo. Cut out the part you need with Cut Audio and analyse it separately.
If the grid starts in the wrong place, for example on an upbeat, the tempo can still be correct; only the position of the first beat is off. Listen whether the clicks are evenly between the drum hits or on them. A file that begins with silence or a long intro without drums gives the detection less to work with, so trimming the intro before analysing can help.
In these cases you can also tap the tempo yourself with the BPM counter. Once you know the BPM, set it in the metronome to practise along, or use Change Speed to bring a song to a different tempo.