BPM Detector — Find the Tempo & Key of Any Song
Drop an audio file and get its BPM, musical key and Camelot code in seconds. Analysis runs locally in your browser — free, private, no sign-up.
Drop an audio file here
or click to browse — MP3, WAV, M4A, FLAC, OGG
100% local analysis — your file never leaves this device
- 100% local — files never uploaded
- Results in seconds
- BPM + key + Camelot
How the BPM detector works
Drop your file
MP3, WAV, M4A, FLAC or OGG, up to 150 MB. Your browser decodes it — the file never leaves your device.
Beat & pitch analysis
A spectral-flux onset envelope finds the pulses; tempo comes from the dominant beat frequency, key from chroma vs. Krumhansl-Kessler profiles.
Read & fix the result
You get BPM, key and Camelot instantly. If the metrical level looks wrong, one tap on ½× or 2× corrects it.
Under the hood this is the same signal-processing pipeline commercial DJ software uses, rebuilt to run entirely in JavaScript: a short-time Fourier transform turns the waveform into spectra, the positive flux between consecutive frames becomes the onset curve, and the tempo is read from that curve’s dominant frequency with an octave-aware scoring pass. Because everything is deterministic and local, results are reproducible and your music stays yours.
Who uses a BPM detector
DJs
Tag your library with BPM, key and Camelot codes, plan beatmatched and harmonic sets, and spot grid errors before the crowd does.
Producers & remixers
Check a sample’s original tempo before you time-stretch it, and its key before you pitch it into your project.
Runners & fitness
Match songs to your cadence — most efficient running form sits at 170–180 steps per minute — and build playlists that hold the pace.
Musicians & dancers
Find the tempo of a backing track for practice, or count the BPM of choreography music without a metronome app.
Video editors
Know a track’s exact BPM so you can cut transitions on the beat and sync b-roll to the pulse.
Lighting & VJs
Feed accurate tempos to your lighting console or visual software so cues land on the kick, not near it.
Half or double? Reading BPM correctly
Every tempo detector — including the ones inside Rekordbox, Serato and Engine — occasionally locks onto the wrong metrical level and reports 85 for a 170 BPM drum & bass track, or 140 for a 70 BPM ballad. That’s not a bug: a beat grid at twice the spacing is mathematically valid, so software has to guess which level humans perceive. This detector prefers the level closest to 120 BPM and gives you a one-tap ½× / 2× correction, which is faster than re-analyzing in desktop software. Typical genre ranges help you sanity-check:
| Genre | Typical BPM |
|---|---|
| Ballads / slow soul | 60–80 |
| Hip-hop / boom bap | 80–100 |
| Pop / R&B | 100–130 |
| House | 120–128 |
| Techno | 130–140 |
| Trap / dubstep | 130–150 |
| Drum & bass | 170–176 |
| Rock / metal | 110–180 |
Tap Tempo — count the BPM by hand
For live music, vinyl rips or awkward files, your finger is still the most honest detector. Play the track, tap the button on every beat, and the average converges within a few taps — no file needed. It’s also the fastest way to double-check an automatic result you don’t trust.
Tap the button along with the beat — at least 4 taps for a stable reading.
Your files never leave your device
Most online BPM detectors upload your music to a server, analyze it there, and hope you don’t mind. This one doesn’t: decoding and analysis run in your browser tab, and the moment you close the page nothing remains — no copies, no queue, no storage bill. It also means unreleased tracks, acapellas and client stems stay private by default, which is exactly how audio professionals want it. The page works offline once loaded; you can drop your Wi-Fi and keep detecting.
Frequently Asked Questions
Everything people ask before trusting a BPM detector with their music.