Find the BPM and key of any track

Drop an audio file. The analyzer decodes it on your device, finds the tempo and musical key, and returns a Camelot code for harmonic mixing.

Choose a file

BPM and key analyzer

Files never leave your device.

  • Files stay local. There is no upload endpoint.

  • Works with MP3, WAV, M4A, OGG, and WebM.

  • Results include BPM, musical key, and Camelot wheel code.

Three steps, no upload

The heavy analysis code loads only after you choose a file. Until then, the page stays small.

  1. 01

    Choose a file

    The browser decodes the audio into raw samples. The file is never sent over the network.

  2. 02

    Analyze a bounded section

    Up to two minutes are analyzed, with long intros skipped so a beatless opening does not skew the tempo.

  3. 03

    Read the result

    Tempo comes from beat detection. Key comes from a chroma profile matched against Krumhansl–Schmuckler key profiles.

What the numbers mean

Enough context to use the result without opening a music theory textbook.

BPM
Beats per minute. A 128 BPM track has 128 quarter-note beats in one minute, which is the common range for house and techno.
Key
The tonic and mode the track resolves to, such as C♯ minor. Tracks in the same key share a tonal center; relative and adjacent keys share most notes.
Camelot
A wheel that labels compatible keys. Same number with A or B mixes cleanly, and moving one number up or down usually stays musical.

Questions

Is my audio file uploaded anywhere?

No. The file is decoded and analyzed by your browser. There is no upload endpoint, no account, and no server-side audio processing.

Which audio formats can I use?

MP3, WAV, M4A, AAC, OGG, and WebM work in current browsers. FLAC support depends on the browser. The limit is 80 MB per file.

How accurate are the BPM and key results?

Tempo detection works best on music with a steady beat, especially electronic and dance tracks. Key detection uses a chroma profile and the Krumhansl–Schmuckler algorithm. Sparse, atonal, or heavily modulated tracks can produce ambiguous results.

What is a Camelot code?

The Camelot wheel numbers musical keys by compatibility for harmonic mixing. Tracks with the same number and adjacent letters, such as 8A and 8B, mix cleanly because their scales share most notes.