Circle of fifths
The circle of fifths lines up the 12 major keys a fifth apart: each step clockwise adds a sharp and each step counterclockwise adds a flat. The inner ring holds the relative minors, which share the key signature.
Hover or focus (Tab) a key: its relative minor, the V7 (solid ring) and the IV (dashed ring) light up.
How to read it
Go up a perfect fifth from C and you reach G, which has 1 sharp; another fifth gives D with 2. In the other direction, going down a fifth (or up a fourth) adds a flat: F has 1 flat and B♭ has 2. The relative minor sits a minor third below the major tonic and uses the same notes: A minor is the relative of C. Opposite points on the circle are a tritone apart, which explains tritone substitution below.
The 12 keys
| Major | Key signature | Relative minor | V7 | IVMaj7 |
|---|---|---|---|---|
| C | 0 | Am | G7 | FMaj7 |
| G | 1♯ | Em | D7 | CMaj7 |
| D | 2♯ | Bm | A7 | GMaj7 |
| A | 3♯ | F♯m | E7 | DMaj7 |
| E | 4♯ | C♯m | B7 | AMaj7 |
| B | 5♯ | G♯m | F♯7 | EMaj7 |
| F♯ | 6♯ | D♯m | C♯7 | BMaj7 |
| D♭ | 5♭ | B♭m | A♭7 | G♭Maj7 |
| A♭ | 4♭ | Fm | E♭7 | D♭Maj7 |
| E♭ | 3♭ | Cm | B♭7 | A♭Maj7 |
| B♭ | 2♭ | Gm | F7 | E♭Maj7 |
| F | 1♭ | Dm | C7 | B♭Maj7 |
F♯ and G♭ are the same key under two names (6 sharps or 6 flats); this table uses F♯ and D♭.
The descending fifths cycle
Read counterclockwise, the circle is the cycle of descending fifths, and resolving down a fifth is the strongest motion in tonal harmony. That is why V7 resolves to I (G7 to C) and why II-7 V7 I (Dm7 G7 CMaj7) is the full jazz cadence: each root falls a fifth from the one before.
Secondary dominants
A secondary dominant is a dominant that creates the expectation of resolving down a fifth to a diatonic chord other than the tonic. You get it by chromatically altering the diatonic chord, and in C it gives these five:
| Secondary dominant | Comes from | Target |
|---|---|---|
| A7 (V7/II) | Am7 | Dm7 |
| B7 (V7/III) | Bø | Em7 |
| C7 (V7/IV) | CMaj7 | FMaj7 |
| D7 (V7/V) | Dm7 | G7 |
| E7 (V7/VI) | Em7 | Am7 |
There is no V7/VII: its root would be chromatic and VII ø is too unstable as a target.
Chains of dominants
Dominants can be chained by walking around the circle: E7 resolves to A7, A7 to D7, D7 to G7 and G7 to CMaj7. Each chord is the dominant of the next and every step is a descending fifth.
Tritone substitution
Two dominants on opposite sides of the circle share a tritone (the third and the b7). G7 contains B and F, and D♭7 contains F and C♭ (the same note as B): that is why D♭7 can replace G7 and resolve to C by a descending half step.
Frequently asked questions
What is the circle of fifths?
It is the diagram that orders the 12 keys a fifth apart and shows how many sharps or flats each one has.
How do I find the key signature of a key?
Start at C and move one fifth per step: each step clockwise adds a sharp (G 1, D 2, A 3, E 4, B 5, F♯ 6) and each step counterclockwise adds a flat (F 1, B♭ 2, E♭ 3, A♭ 4, D♭ 5).
What is the relative minor of a major key?
The minor key a minor third below that shares the key signature. The relative of C is A minor, of G is E minor and of F is D minor.
Based on the jazz harmony principles of Joe Mulholland and Tom Hojnacki (Berklee Press).
Intervals · American chord notation · Scales and modes in every key