Online Tool Store
BPM Detector
Analyze audio locally to estimate beats per minute, confidence, beat spacing, and half or double tempo, with a tap-tempo cross-check.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Local tempo analysis
Midnight-drive.mp3
Example track · 3:42 · rhythmic electronic
Detected tempo
87% rhythmic confidence
- Beat interval
- 482 ms
- Tempo feel
- Allegro
- Half time
- 62.3
- Double time
- 249.2
Example result shown. Choose audio for a local tempo estimate, or tap repeatedly to cross-check a beat.
How to detect a song's BPM
- Choose an audio file with a reasonably clear rhythmic section.
- Analyze its onset intervals locally and review the BPM and confidence.
- Check the half/double-time options or tap along to verify the musical pulse.
Onset-interval method
The detector measures short-window signal energy and marks prominent local peaks. Repeated time gaps between peaks vote for tempo candidates, which are normalized into a practical 60–200 BPM range. This lightweight method is useful for steady material but is an estimate rather than a full beat-grid analysis.
FAQ
What does BPM mean?
BPM means beats per minute. At 120 BPM, a regular beat occurs twice per second.
How does the detector estimate tempo?
It divides decoded audio into short windows, finds strong rhythmic energy onsets, compares intervals between them, and selects the most repeated tempo candidate.
Why might the result be half or double the expected BPM?
Tempo has metrical ambiguity. An analyzer may lock onto every beat, every second beat, or subdivisions, so half-time and double-time candidates are shown.
What audio works best?
Tracks with a steady pulse and clear drum transients are easiest. Rubato performances, changing tempo, ambient audio, and speech may not yield a stable result.
Is my audio uploaded?
No. The browser decodes and analyzes the selected file locally with the Web Audio API.
How we compare
| Feature | Online Tool Store | Tunebat Analyzer | AudioAlter BPM Detector |
|---|---|---|---|
| Audio-file BPM estimate | Included | Included | Included |
| Tap-tempo cross-check | Included | Separate tapper | Dedicated detector |
| Key and broader audio features | Not included | Included | Separate audio tools |
| Browser-local analysis | Included | Upload analyzer | Upload workflow |
Choose Tunebat when you also need key and broader track features, or AudioAlter for its wider collection of audio processors. Choose Online Tool Store for a private local onset estimate with confidence, half/double-time context, and tap verification.