Music theory

The circle of fifths, interactive.

Click any key on the wheel — see its key signature, relative minor, and the seven chords that live in that key.

CAmGEmDBmAF♯mEC♯mBG♯mF♯D♯mD♭B♭mA♭FmE♭CmB♭GmFDmMAJORminor
Selected key

C major

A minor
Key signature
No sharps or flats — open key.
Chords in this key
I
C
ii
D
iii
E
IV
F
V
G
vi
A
vii°
B

How to read the circle

Each key on the wheel is a perfect fifth above its counter-clockwise neighbour. Going clockwise adds one sharp; going counter-clockwise adds one flat. The relative minor sits inside each major slice — same key signature, different mood.

Why piano players use it

The closer two keys sit on the wheel, the more notes they share. So modulating to a neighbour (e.g. C → G) sounds smooth — pop songs do this constantly. Distant pairs (C → F♯) sound dramatic.