The circle of fifths arranges the 12 keys so that neighbors differ by exactly one accidental. It is the map of key relationships.
Move clockwise and each key adds one sharp (C, G, D, A, E, B, F#); counter-clockwise adds flats (F, Bb, Eb, Ab, Db, Gb). Sharps arrive in the fixed order F#-C#-G#-D#-A#-E#-B#; flats mirror it exactly.
Every major key shares its signature with a relative minor three semitones below it. Neighboring keys share six of seven notes, which is why modulations to the dominant or subdominant sound smooth.
| Major key | Signature | Relative minor |
|---|---|---|
| C | no sharps or flats | A minor |
| G | 1 sharp (F♯) | E minor |
| D | 2 sharps (F♯ C♯) | B minor |
| A | 3 sharps | F♯ minor |
| E | 4 sharps | C♯ minor |
| B | 5 sharps | G♯ minor |
| F♯ | 6 sharps | D♯ minor |
| F | 1 flat (B♭) | D minor |
| B♭ | 2 flats (B♭ E♭) | G minor |
| E♭ | 3 flats | C minor |
| A♭ | 4 flats | F minor |
| D♭ | 5 flats | B♭ minor |
| G♭ | 6 flats | E♭ minor |
Common questions
How do I find the key from sharps or flats?
Sharps: the key is a semitone above the last sharp. Flats: the key is the second-to-last flat (one flat alone is F major).
What is a relative minor?
The minor key sharing a major key’s signature, rooted on its 6th degree, three semitones below the major tonic. C major’s relative is A minor.