Song key finder
The key of a track, and the number a DJ mixes it by.
Drop files here
or click to choose from your deviceAccepted: MP3, M4A, AAC, WAV, OGG, OGA, OPUS, FLAC, WEBA, MP4, M4V, WEBM, MOV, MKV
Up to 3 files per runUp to 20 MB per file5 runs per dayRemove limits with Pro✓ Works offline
Your files stay on your device
This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.
Example
Example: a Gm–E♭–B♭–F loop reads B♭ major 6B, with G minor 6A next
A singer records a 32-second piano loop to choose a key for a cover: four chords of two seconds each, G minor, E♭, B♭ and F, round and round. She drops in the WAV file; a recording shorter than a minute is measured whole.
- The page shows “B♭ major Camelot 6B” and under it “next closest: G minor Camelot 6A”, and saves the same two lines as a text file ending in -key.txt.
- B♭ major and G minor are relative keys: the same seven notes and Camelot number, only the letter differs. With four chords given equal time, the notes alone cannot say which is home.
- The ear decides the name: if the song comes to rest on G minor, call it G minor. The notes, and the mixing number 6, are the same either way.
- The same test with Am–F–C–G reads C major 8B, next closest A minor 8A.
| Camelot | Key | Relation to the loop |
|---|---|---|
| 6B | B♭ major | the result |
| 6A | G minor | the runner-up, its relative minor |
| 5A | C minor | one step from 6A |
| 7A | D minor | one step from 6A |
| 5B | E♭ major | one step from 6B |
| 7B | F major | one step from 6B |
The loop is in B♭ major or G minor, Camelot 6B or 6A. Tracks with the same number, or one step away on the same letter, mix with it without clashing.
How it works
- Add a track — MP3, M4A, WAV, FLAC, or a video, whose sound is read.
- Wait a moment: a minute from the middle of the track is measured note by note.
- Read the key and its Camelot number, with the next closest key under it.
- Mix with tracks whose Camelot number is the same or one step away, or transpose to match.
Frequently asked questions
- How does it work?
- It measures how much of each of the twelve notes is sounding across five octaves, then compares that with the profiles Krumhansl and Kessler measured for major and minor keys. The key whose profile fits best is the answer.
- What is the Camelot number?
- The wheel DJs use: C major is 8B and its relative minor, A minor, is 8A. Tracks with the same number, or one step around the wheel, or the same number in the other letter, generally mix without clashing.
- How accurate is it?
- Good on music with clear harmony. The common mistake is between a key and its relative — A minor and C major share every note, and only emphasis tells them apart — which is why the next closest key is printed too. A track that changes key has no single answer.
- Does it read the whole track?
- A minute from the middle, so a quiet intro or a long fade-out does not mislead it. A recording shorter than a minute is read whole, and one under about three seconds is refused. If the key changes within that minute, the result mixes both: check it by ear.
- Can I check several tracks at once?
- Yes. Add several and each gets its own result and its own -key.txt file. On the free plan that is 3 tracks a run.
- Is my music uploaded, and what are the free limits?
- No. It is analysed in your browser and nothing leaves your computer. The free plan takes 3 tracks per run of up to 20 MB each, and 5 runs a day: a four-minute MP3 fits easily, a four-minute WAV (about 40 MB) does not — use the MP3, the key is the same. Pro removes the limits.