Circle of Fifths

The circle of fifths, made interactive

The circle of fifths is one of the most useful diagrams in music theory. It places the twelve keys around a circle so that each clockwise step moves up a perfect fifth, from C to G to D and onwards until the circle closes back at C. Going the other way moves up by fourths. This simple arrangement reveals the key signature of every key, which keys are closely related, and why certain chord progressions sound so natural.

Click any segment to select a key. The outer ring holds the major keys and the inner ring the relative minors, which use the same notes. The panel shows the key's relative major or minor, its key signature with the sharps or flats in the order they are written on the staff, the notes of the scale, and the seven diatonic chords with Roman numerals. The segments next to your selection light up to show the neighbouring keys, and a button plays the tonic chord so you can hear the key's home sound.

Reading key signatures

Starting from C major, which has no sharps or flats, each step clockwise adds one sharp: G has F♯, D adds C♯, A adds G♯ and so on, always in the order F♯ C♯ G♯ D♯ A♯ E♯ B♯. Each step counter-clockwise adds one flat in the order B♭ E♭ A♭ D♭ G♭ C♭ F♭, so F has one flat and B♭ has two. At the bottom of the circle the sharp and flat keys meet, which is where enharmonic keys such as F♯ and G♭ major appear.

Using the circle to write and analyse music

Neighbouring keys differ by only one note, so modulating to them sounds smooth. The three major chords of any major key — I, IV and V — sit side by side on the circle, and the minor chords ii, iii and vi are the relative minors directly inside them. Many progressions also move around the circle, such as the ii–V–I cadence or the circle progression vi–ii–V–I. Use this tool to find chords that fit together, to transpose songs, or to memorise key signatures quickly.