Key Finder
Find out what key a song is in. Play it into your microphone — on your instrument, by singing, or from a speaker — or type its chords.
What it has heard
Press Start listening, then play the song on your instrument or from a speaker near the microphone. Chords, a melody or a whole recording all work.
How to Find the Key of a Song
- Press Start listening and allow the microphone.
- Play the song: strum the chords, sing or hum the melody, or play the recording from a speaker near your phone or computer.
- Keep going for a verse and a chorus. The bars show which notes it has heard most; the key appears after a few seconds and firms up as it hears more.
- Check the relative key. If the song feels like it settles on the minor chord, it is in the relative minor.
If you already have the chords from a chord sheet, switch to Type the chords and enter them in order. That mode checks which key the chords belong to and gives extra weight to the first and last chord, which are usually the home chord.
What "Key" Means
A song's key is the scale its notes are drawn from and the chord it treats as home. A song in G major uses the notes of the G major scale, its chords are mostly the seven chords built from that scale — G, Am, Bm, C, D, Em and F♯dim — and it feels finished when it lands on G. The circle of fifths lists the chords for every key.
Knowing the key tells you which scale to solo with, which chords are likely to come next, and how far to move a song to suit your voice. To play it in another key, the chord transposer rewrites the chords, and the capo calculator finds a capo fret that keeps the shapes easy.
Getting a Reliable Result
- Reduce other sound. Fans, traffic and the TV all add notes. A quiet room gives a cleaner profile.
- Play the whole progression. Two chords can belong to half a dozen keys; four to eight usually belong to one.
- Let chords ring. Sustained chords give a clearer picture than heavily muted rhythm playing.
- Check a borderline result by ear. Turn on the drone generator in the key it suggests and play along. If the song sits comfortably over the drone, the key is right.
Modes and Borrowed Chords
Not every song fits a plain major or minor key. Blues and rock songs often use a major chord on the root with a flat seventh (Mixolydian), and minor songs often swap in a major V chord from the harmonic minor. The key finder will still give the closest major or minor key — usually the right root — and the scale explorer shows the modes that fit songs that lean outside it.
Frequently Asked Questions
How does the key finder work?
It listens to the sound, measures how much of each of the twelve notes it hears over time, and compares that profile with how strongly each note belongs to each of the 24 major and minor keys. The key whose profile matches best is the answer. It never needs to name individual notes, which is why it works on chords and full recordings, not just single notes.
Is my audio recorded or uploaded?
No. The analysis runs in your browser, on your device, and only a running total of twelve numbers is kept. Nothing is recorded, stored or sent anywhere. Stopping the key finder releases the microphone.
Why does it say a major key when the song sounds minor?
Every major key has a relative minor that uses exactly the same notes — C major and A minor, G major and E minor. From notes alone the two are close, and the key finder shows both. The one the song is really in is the one it feels like it comes home to: listen to the last chord, and the chord the chorus lands on.
How long should I play for?
At least a verse and a chorus — 20 to 30 seconds. The first guess appears after four seconds, but a few chords can belong to several keys, and the answer settles as more of the song is heard. Press Start over to clear what it has heard before trying a new song.
What if a song changes key?
The key finder adds up everything it hears, so after a key change it will show a blend that may match neither key well. Start over at the key change to analyse the new section on its own.
Which mode is more accurate?
If you know the chords, typing them is the most reliable, because it removes room noise and overtones from the question. Listening is better when you do not know the chords, or the song is a melody with no chords at all.