Circle of Fifths
The twelve keys arranged in a ring by ascending fifths, so that neighbors share almost all their notes and sharps or flats accumulate one step at a time.
Contents
Circle of Fifths
The circle of fifths is the single most useful map in music. Arrange the twelve keys around a clock so that each step clockwise rises by a perfect fifth — C, G, D, A, E, … — and a remarkable order emerges: neighbors on the circle are the keys most closely related, sharing all but one of their notes, and the sharps and flats pile up one at a time as you travel around.
Reading the ring
Start at C at the top, with no sharps and no flats. Each step clockwise (up a fifth) adds one sharp: G has one (F♯), D has two, A has three, and so on. Each step counter-clockwise (down a fifth, i.e. up a fourth) adds one flat: F has one (B♭), B♭ has two, E♭ has three. Walk far enough either way and the sharp and flat spellings meet at the bottom of the circle — the same pitches, written two ways.
Why fifths? Because the perfect fifth is the most consonant Interval after the octave, keys a fifth apart overlap heavily, so moving between them sounds smooth. That is exactly why the strongest moves in Harmony are also moves by a fifth.
Spin the circle
Click any key to select it. The selection lights up along with its two neighbors — the keys a fifth above and below, its closest relatives. The readout names the key and counts its sharps or flats.