Free Online BPM & Key Finder
Find the tempo and musical key of any song.
Drag & drop your audio file here
or
Max file size: 100 MB · MP3, WAV, FLAC, OGG
Original
beats per minute
musical key
No settings needed - analysis runs automatically once your file is decoded, and the detected tempo and musical key appear as big readouts.
Processing…
Result
How it works
The BPM & Key Finder analyzes your audio to find its tempo in beats per minute. It works by tracking onsets - the rhythmic attacks of drums, bass notes and strums - building a picture of where the beats fall, then finding the pulse rate that best explains them. The result comes with a confidence score so you know how much to trust it.
A note on accuracy: beat tracking is genuinely hard. Steady electronic and pop tracks are detected near-perfectly, but half-time feels, swung jazz, tempo changes and beatless ambient pieces can confuse any detector, human or machine. If a number looks off, doubling or halving it usually reveals the intended tempo.
Analysis is 100% client-side: your music is decoded and analyzed inside your own browser tab, so files never leave your device and nothing is ever uploaded to a server.
The musical key readout is computed from a chromagram of the track - the distribution of energy across the twelve pitch classes - matched against the Krumhansl-Schmuckler key profiles, the same statistical method used in music-information-retrieval research. The Camelot code beside it (for example, 8A for A minor) is the harmonic-mixing shorthand DJs use to blend compatible tracks. Key detection is honest about its limits: it shines on tonal songs with a stable key and is less reliable on ambient, atonal or key-changing material.
Frequently asked questions
How accurate is the BPM detection?
Very good on music with a clear, steady beat - electronic, pop, hip-hop and rock typically land within 1 BPM. It can be fooled by half-time/double-time feels (reporting 70 instead of 140), rubato classical pieces, ambient music with no beat, and songs with tempo changes. Always trust the confidence score and your ears.
Why does it show half or double the expected BPM?
Beat tracking has a classic octave ambiguity: a 140 BPM drum-and-bass track and a 70 BPM halftime groove have energy at both rates. If the number feels wrong, try doubling or halving it.
Does it work on speech or ambient recordings?
Not meaningfully - with no rhythmic pulse to lock onto, the detector returns a low-confidence guess. It is designed for music with a beat.
Is there a file size limit? Is it private?
Files up to 100MB are supported. Analysis runs entirely in your browser - your music never leaves your device.
How is the musical key detected?
The audio is reduced to a chromagram - a 12-bin profile showing how much energy sits on each pitch class (C, C#, D, ...). That profile is then compared against the classic Krumhansl-Schmuckler key profiles (the statistical fingerprint of each major and minor key) and the best match wins. It works best on tonal music with a clear key; atonal, ambient or constantly modulating music can confuse it, as can tracks with long intros in a different key.
What is the Camelot code?
The Camelot code is the DJ-friendly shorthand for a musical key, used for harmonic mixing: 8A means A minor, 8B means C major, and so on. Mixing tracks whose codes match (or differ by one step, like 8A into 9A) keeps the keys compatible, so blends sound smooth instead of clashing.