Analyzes the pitch content of a track and matches it against known major/minor key profiles (the Krumhansl-Schmuckler method) to estimate its musical key.
The Key Finder detects the musical key of a recording — for example F♯ minor — and gives the DJ notations (Camelot and Open Key), the relative major/minor and how far the recording is tuned from A = 440 Hz.
Press “Play tonic chord” or “Play the scale” to hear the detected key and check it against your ear; sustained, tonal music gives the most reliable result.
Up to 45 seconds from the middle of the track are transformed with an 8192-point FFT; spectral peaks are used to estimate the recording’s tuning offset (so music tuned a little sharp or flat is not misread). Energy between 65 Hz and 2.2 kHz is folded into 12 pitch classes with fractional-semitone weighting, then correlated against the Krumhansl–Schmuckler major and minor key profiles for all 24 keys. The best correlation is the key; the gap to the runner-up indicates confidence.
Choose compatible tracks with the Camelot wheel.
Pick scales and chords that fit a sample.
Find the key to match a vocal range.
Know what key to play in.
| Method | Chroma + Krumhansl–Schmuckler profiles |
|---|---|
| Output | Key, Camelot, Open Key, relative key, tuning |
| Keys tested | 24 |
A DJ notation that numbers keys 1–12 with A (minor) or B (major); neighbours mix harmonically.
How many cents the recording is sharp (+) or flat (−) relative to A=440.
It builds a 'chroma' profile — how much energy is present at each of the 12 pitch classes (C, C#, D, and so on) — then compares that profile against the Krumhansl-Schmuckler major and minor key templates from music cognition research, picking the best match.
Relative major/minor pairs (like C major and A minor) share the same notes and can be confused, especially on short or sparse excerpts. Heavily processed, atonal, or key-changing tracks are also harder to pin to one key.
It's a correlation score between your track's pitch profile and the matched key template — closer to 1.0 means a cleaner, more confident match.
This tool runs entirely in your browser using the Web Audio API. Nothing is uploaded, stored or shared — there is no server to send your file to, so it works offline once the page has loaded.
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