Circle of Fifths

Tap a key. Its neighbors light up with their function, and the inner ring shows the relative minors. Switch between major and minor — or tap an inner key directly for minor.

C majorA minorG majorE minorD majorB minorA majorF♯ minorE majorC♯ minorB majorG♯ minorF♯ majorD♯ minorD♭ majorB♭ minorA♭ majorF minorE♭ majorC minorB♭ majorG minorF majorD minorCAmIviGEmViiiDBmAF♯mEC♯mBG♯mF♯D♯mD♭B♭mA♭FmE♭CmB♭GmFDmIViiCmajor · Am

Clockwise = up a fifth (more ♯, toward the dominant).
Counter-clockwise = down a fifth (more ♭, toward the subdominant).

C major · no sharps or flats · relative minor Am
Clockwise → G (V, dominant). Counter-clockwise → F (IV, subdominant). Each step changes just one note.
The six most common chords in C — outer: I C, IV F, V G; inner: ii Dm, iii Em, vi Am.