How to find the key of a song
- Choose an MP3, WAV or M4A file up to 10 minutes long.
- Wait a few seconds while the key finder listens to the whole track.
- Read the key and its Camelot code. If the song sounds darker or brighter than the result, the relative key next to it is the other likely answer.
How this song key finder works
First it splits the song into short, overlapping slices and runs each one through a Fourier transform, which shows how much energy sits at every frequency. It keeps only the clear peaks between about 60 Hz and 2 kHz, where bass lines, chords and melodies live, so drum hits and noise count for very little.
Every peak is then turned into a note and folded into one of the 12 pitch classes, so a low C and a high C both count towards C. Before that, the tool measures how the recording is tuned. Plenty of songs sit a bit sharp or flat of the usual A = 440 Hz, and without that step a detuned song could land halfway between two keys.
The result is a profile of which notes the song uses most, called a chroma vector. The key finder compares it with the Krumhansl-Kessler profiles, which come from music psychology research into how strongly each note belongs to each of the 24 major and minor keys. The closest match is the key. This method is known as the Krumhansl-Schmuckler algorithm. The confidence shows how far ahead the winner is of the next best key that isn’t its relative.
Major or minor? Relative keys explained
C major and A minor use the same seven notes, the white keys on a piano. What makes a song one or the other is which note feels like home. A song in C major keeps resolving to C and usually sounds bright. A song in A minor keeps landing on A and sounds darker. Because the notes are the same, any key finder can mix the two up, which is why the result shows both. Listen to where the song settles at the end of a section: that note is usually the key.
The Camelot wheel
DJs use the Camelot wheel to mix songs in key. Each key gets a number from 1 to 12 and a letter: A for minor, B for major. Songs with the same code, or with a number one step away and the same letter, share most of their notes and blend without clashing.
| Number | Minor (A) | Major (B) |
|---|---|---|
| 1 | 1A · G♯ minor | 1B · B major |
| 2 | 2A · E♭ minor | 2B · F♯ major |
| 3 | 3A · B♭ minor | 3B · D♭ major |
| 4 | 4A · F minor | 4B · A♭ major |
| 5 | 5A · C minor | 5B · E♭ major |
| 6 | 6A · G minor | 6B · B♭ major |
| 7 | 7A · D minor | 7B · F major |
| 8 | 8A · A minor | 8B · C major |
| 9 | 9A · E minor | 9B · G major |
| 10 | 10A · B minor | 10B · D major |
| 11 | 11A · F♯ minor | 11B · A major |
| 12 | 12A · C♯ minor | 12B · E major |
Moving up one number is the same as moving up a fifth, so 8A (A minor) to 9A (E minor) sounds natural. Switching letters with the same number moves between relative keys, like 8A to 8B, and keeps every note the same.
FAQ
How do I find the key of a song?
Choose the song as an MP3, WAV or M4A file and the key finder starts listening right away. In a few seconds you get the key, its relative major or minor, the Camelot code and how sure the result is.
How accurate is the song key finder?
For songs that stay in one key, with clear chords, bass or a melody, it usually gets it right. The most common miss is the relative key, like C major instead of A minor, because those two keys use exactly the same notes. That’s why the result always shows the relative key next to the main one.
What is a relative major or minor key?
Every major key shares its notes with one minor key, three semitones lower. C major and A minor, G major and E minor, and E♭ major and C minor are pairs. The notes are the same, but the song centers on a different home note, so the minor one sounds darker.
What does the Camelot code mean?
The Camelot wheel gives each key a code from 1A to 12B so DJs can mix in key without music theory. A is minor and B is major. Two songs mix smoothly when they share a code, or when the number is one step apart with the same letter, like 8A to 9A.
Can it find the key of a beat or a sample?
Yes, as long as it has notes in it: chords, a melody, 808s or a vocal. A loop with only drums doesn’t really have a key, so the result will say low confidence. For a sample, check the key here, then move it to your beat’s key with the pitch shifter.
Is my song uploaded?
No. The key finder runs in your browser, so your file never leaves your device. It’s free and there’s nothing to sign up for.