MotionLyric

● Free · private · runs in your browser

Key Finder

Find the musical key of any song. Drop in an audio file and get the key, its relative key and Camelot code. You also see the evidence: which notes the song leans on, and how close the runner-up came.

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MP3, WAV, M4A, FLAC or OGG. Analysed on your device, never uploaded.

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Key

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Camelot
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Relative key
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Confidence
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Tuning
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The notes the song uses most, and how well each key fits them, appear here after analysis.

Pitch profile · notes of the key highlighted

  1. C
  2. C♯
  3. D
  4. E♭
  5. E
  6. F
  7. F♯
  8. G
  9. A♭
  10. A
  11. B♭
  12. B

Best matches

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Make a lyric video with this songLoad a song above and it comes with you into the editor.

Open it in the lyric video maker →

How the key finder works

A key is a home note plus a set of notes that belong with it. To find it, the tool listens for which notes the song uses and how much, then asks which key would produce that pattern.

  1. Pitch profile. The song is split into short overlapping slices and each slice is turned into a spectrum. The tonal peaks in the spectrum are folded onto the 12 note names, C to B, across six octaves. The result is a 12-bar profile: the chart above.
  2. Tuning. Before folding, the tool measures how far the song sits from A = 440 Hz and corrects for it, so a song tuned a quarter-tone flat is not read as the key next door.
  3. Matching. The profile is compared with the Krumhansl–Schmuckler key profiles, which come from listening experiments that measured how well each note fits a given key. They are rotated to all 12 home notes in major and minor, and the closest of the 24 wins.

The analysis gives the same answer every time for the same file, and all of it happens in your browser. Once you know the key, you can take the song into the lyric video maker with the button above, or check its tempo with the BPM finder.

When the key finder can be wrong

The Camelot wheel

DJs use the Camelot codes to mix in key: keep the same number, move one step either way, or switch between A and B on the same number.

CodeMajor keyCodeRelative minor
1BB major1AG♯ minor
2BF♯ major2AE♭ minor
3BD♭ major3AB♭ minor
4BA♭ major4AF minor
5BE♭ major5AC minor
6BB♭ major6AG minor
7BF major7AD minor
8BC major8AA minor
9BG major9AE minor
10BD major10AB minor
11BA major11AF♯ minor
12BE major12AC♯ minor

Key finder questions

How accurate is the key finder?

On test recordings built in a known key, it names the right key in all 24 major and minor keys, including recordings tuned up to 40 cents away from standard pitch and recordings with added background noise. Real songs are harder: the most common disagreement is between a key and its relative (C major and A minor share the same notes). The result shows the runner-up and how close it was, so you can see when the call is a narrow one.

Is my song uploaded?

No. The audio is decoded and analysed by your browser. Nothing leaves your device, which is why the tool also works with unreleased mixes.

What is a relative key?

Every major key shares its key signature with one minor key, three semitones lower: C major and A minor, G major and E minor, and so on. They use the same notes but a different home note, so songs often move between them. They also share the same Camelot number.

What does the Camelot code mean?

The Camelot wheel numbers the 24 keys so DJs can mix harmonically without music theory: tracks with the same code, one number up or down, or the same number with A and B swapped usually blend without clashing. B codes are major keys, A codes are minor.

What do the tuning cents mean?

A cent is a hundredth of a semitone. Most music is tuned to A = 440 Hz; some is tuned a little higher or lower on purpose, or drifts because of tape speed or a detuned instrument. The finder measures that offset and corrects for it before naming the key.

Why is the result marked ambiguous?

Because two keys fit almost equally well. That happens with songs that change key, songs built on a few repeated chords, modal music, and very sparse or percussive tracks. Listen to which note feels like home at the end of a phrase; that is usually the tonic.