What Key Is This Song In?
Type in the chords you're playing and get the key instantly — then learn the quick tricks to work it out on your own, and see it on the circle of fifths.
- Find the song's chords.Look at a chord sheet — the letters printed above the lyrics (on a tab site, in a songbook, or wherever you're learning it).
- Read each chord name: a plain letter like C G D is major; a letter with an m (Am, Em) is minor; a letter with a 7 (G7, D7) is a dominant 7. The dropdown carries the rest — maj7, m7, m7♭5, dim, °7, +, 5, sus2, sus4, 6, m6, add9, 9 — so enter what the sheet actually says. The exact quality is a real clue: only one key has Cmaj7 as its home chord.
- Add each different chord using the picker below. You only need one of each — ignore repeats. Be sure to include the first and last chords of the song; they're the biggest clues.
- Read the result. The tool names the most likely key and shows why. If two keys tie, hum the tune and notice which note feels like “home”.
- ✓It starts on G — the ear hears the opening chord as “home.”
- ✓4 of your 4 chords belong to G major.
Why it works: chords belong to a key
Almost every song stays inside one key — a set of seven chords built from one scale (I ii iii IV V vi vii°). So if you list a song's chords and find the one key that contains all of them, you've found the key. That's exactly what the finder above does: it scores all 24 keys and picks the best fit.
Do it by ear in three checks
- First and last chord. Songs love to start and end on the I chord— the key itself. That's your best single clue.
- Find the dominant 7th. A 7 chord (like G7) is almost always the V, so the key sits a fourth above it — G7 points to the key of C.
- Major or minor? A major key and its relative minor share all their chords, so let your ear decide which note feels like home. Bright = major; darker = the relative minor.
See it, then use it
Once you know the key, the interactive tool lights up all seven of its chords and the scale to solo with, and the circle of fifths shows why they belong together. Knowing the key also lets you number the chords and transpose or capo the song to any other key.
Reading only gets you so far — open the interactive fretboard and watch these ideas light up on guitar and piano.
Enter the toolFrequently asked
How do I find the key of a song from its chords?
Almost every chord in a song comes from one key's diatonic set (I ii iii IV V vi vii°). Match the chords to the key that contains all of them — the tool above does this for you. The song usually starts and/or ends on the I (or i) chord, which is the key.
What is the fastest way to tell the key?
Look at the first and last chords — they're very often the I chord, i.e. the key. Then check for a dominant-7th chord: it's almost always the V, so the key is a fourth above it (or a fifth below).
How do I know if a song is major or minor?
A major and its relative minor share the same chords, so listen for which note feels like 'home'. Bright and resolved usually means major; darker and more serious usually means the relative minor (three semitones below the major).
Why do two keys show up for my chords?
Because a major key and its relative minor use the same seven chords. The chords can't tell them apart — only the melody and which chord feels like the resting point can. Play both and trust your ear.