BPM Detector Online
or drop files here
BPM Detector
Estimate a song’s beats per minute and compare alternate tempo candidates. An onset-energy envelope and normalized autocorrelation estimate periodic beats. Half-time and double-time ambiguity is common; the score is an estimate, not musical certainty.
- Dedicated bpm detector controls
- Local JSON tempo report export
- Ranked tempo candidates
Find recurring attacks
The detector builds a short-time onset-energy envelope and searches for recurring intervals. Percussive music with a stable pulse generally supplies clearer evidence than ambient pads or free-time speech.
Read candidate scores
The strongest correlation becomes the displayed estimate. Other local peaks remain visible because a rhythm can support several plausible pulse interpretations; scores express periodicity strength, not calibrated certainty.
Resolve half-time ambiguity
An apparent 80 BPM groove may also be counted at 160 BPM. Tap along to the snare and musical phrasing, then narrow the minimum and maximum range to the convention relevant to your project.
Know the analysis window
Up to the first three minutes are analyzed to bound computation. Very short clips and silence return no reliable estimate, while tempo changes inside a song can weaken or split the candidate peaks.
Technical references: Web Audio API specification