BPM Finder

Upload audio and detect BPM automatically in your browser. See tempo, confidence and beat grid.

Drop audio here or click to browse

MP3, WAV, M4A, OGG, FLAC up to ~50 MB — analyzed 100% in your browser

What this BPM Finder offers

Upload audio and detect tempo automatically without tapping. The file is decoded and analyzed 100 percent in your browser with onset detection and autocorrelation between 60 and 200 BPM.

BPM with tempo marking, confidence and matching genres
Duration, beats count and interval display
Waveform with beat grid and audio playback to verify
Half and double check, preview click, copy and send to metronome
Private by design, nothing is uploaded

How to use

Drop an MP3, WAV, M4A or OGG file, or click to browse. Analysis starts automatically.
Wait a few seconds while the tool decodes and analyzes the beat in your browser.
Read BPM, tempo marking, confidence, duration and beats with the waveform beat grid.
Copy the result, try half or double time, or send it to the metronome. Try another file anytime.

What is BPM Finder?

The tool decodes your file, measures energy onsets across time, and finds the repeating pulse with autocorrelation between 60 and 200 BPM.

Confidence reflects how strong the winning tempo is versus other candidates. Clear drums score high, ambient or rubato scores low.

On steady house or hip-hop the grid locks within about 1 BPM and the waveform markers land on transients. On live or rubato recordings the result is an average, so play the file back against the preview click and confirm with the BPM Tapper before producing.

Features

Automatic BPM detection

Onset detection with autocorrelation finds the tempo from your audio without tapping.

Waveform and beat grid

Waveform with beat markers shows where the pulse lands. Play the file to verify by ear.

Half and double check

One click to halve or double if the detector locked to half-time or double-time.

Copy and practice

Copy BPM or send it to the metronome. Everything stays local, nothing is uploaded.

Tips

Use a clear section

Steady drums or a full mix section detects best. Avoid long intros or silence.

Check half and double

If 87 feels like 174, use the double button. Half-time grooves often detect at half tempo.

Verify with tapper

If confidence is low, tap along in the BPM Tapper to confirm by ear.

FAQ

Which audio files work for BPM detection?

MP3, WAV, M4A, OGG and FLAC that your browser can decode, up to about 50 MB. The first 90 seconds are analyzed, so a full-mix chorus with clear drums detects best. Long intros, silence or speech-only sections pull accuracy down.

How accurate is automatic BPM detection?

Within about 1 BPM on steady beat-driven tracks like house, techno, hip-hop and pop. Live recordings, classical rubato, jazz with tempo drift, or sparse ambient return an average instead. High confidence above 80 percent usually means a locked grid, below 55 means verify by ear.

Is my audio uploaded anywhere?

No. The file is decoded with Web Audio and analyzed with onset autocorrelation entirely on your device. No microphone use, no server upload, no storage. Clearing the file revokes the local object URL.

What should I do when confidence is low?

First try half or double with one click, because half-time grooves often lock at 87 instead of 174. Then play the file and preview the click overlay against the waveform beat grid. If it still disagrees, tap the same section in the BPM Tapper for an ear-checked number.

Should I use the Finder or the Tapper?

Use the Finder when you have the file and want tempo plus beat grid without tapping. Use the Tapper for anything you hear without a file: radio, vinyl, live bands, rehearsal rooms. For critical work run both: Finder first, then tap 8 beats to confirm the same number.

How does the detection algorithm work?

It mixes to mono, builds an RMS energy onset envelope, normalizes it, then autocorrelates lags for 60 to 200 BPM and picks the strongest repeating pulse with octave correction. Confidence is the winning peak versus the median candidate. Beat offset comes from the first strong onset for the grid overlay.

References

1. Web Audio API — MDN. developer.mozilla.org/Web/API/Web_Audio_API

2. Tempo detection via onset envelope and autocorrelation between 60 and 200 BPM.

For practice and education. Timing accuracy depends on device performance and browser audio scheduling. For critical recording, compare with a hardware metronome.