The circle of fifths
Scales & modes: Scales · Modes · Beyond scales · Circle of fifths
The circle of fifths is a map of all twelve keys arranged so that each step clockwise jumps up a perfect fifth — and adds exactly one sharp to the key signature. Go counter-clockwise and you add one flat. It's the single most useful diagram in music: it shows how keys are related, where the sharps and flats come from, which minor key shares each major key's notes, and why chords move the way they do.
The wheel — click a key
Click any major key on the outer ring (or its relative minor on the inner ring) to see its notes and hear it. The two neighbours light up as well — they're your IV (one step counter-clockwise) and V (one step clockwise). Playback follows the metronome's tempo (set the BPM in the bar pinned at the bottom).
Why does each step add a sharp (or flat)?
A perfect fifth is seven half-steps — from C up to G. Build the major scale on that new root and you'll find every note is the same as the old key except one, which must be raised to keep the major pattern (W-W-H-W-W-W-H). That one raised note is the new sharp:
- C major = C D E F G A B — no sharps or flats.
- Up a fifth to G major = G A B C D E F♯. Only F changed.
- Up again to D major = D E F♯ G A B C♯. F♯ carries over, C is now raised too.
Going the other way (down a fifth / up a fourth) does the reverse — it flattens one note each step: C → F adds B♭, F → B♭ adds E♭, and so on. Sharps accumulate in the order F C G D A E B; flats in the exact reverse B E A D G C F.
The two sides meet at the bottom: F♯ major (6 sharps) and G♭ major (6 flats) are the same piano keys spelled differently — these are enharmonic keys.
Relative minors — the inner ring
Every major key shares its seven notes with a minor key built on its 6th degree. That's the relative minor, sitting just inside each major on the wheel. C major and A minor use the exact same white keys — they have the same key signature and the same diatonic chords; only home is different.
To find any relative minor quickly: count down three half-steps from the major tonic (C → A, G → E, F → D). To go the other way, count up three (A → C).
Neighbouring keys & chord motion
A key's closest relatives are its two neighbours on the circle. For C those are F (its IV) and G (its V) — together with the relative minors they give you the six chords behind most songs: I, IV, V and their relative minors vi, ii, iii.
Chords love to move counter-clockwise around the circle — each step is a strong "falling fifth". That's exactly what the jazz cadence ii → V → I and the classic V → I resolution are: motion toward home along the circle. See it in action on the chord cheat-sheet and play-along songs.
How to use it
- Read key signatures instantly. Count the sharps or flats and the circle tells you the key: 2 sharps = D major (or B minor).
- Transpose. To move a song up a step or two, rotate every chord the same number of positions around the wheel.
- Practise in all keys. Work scales and drills clockwise around the circle — that's the Circle of Fifths Grind routine.
- Build progressions. Pick a key, then borrow its neighbours and relative minors — you'll be writing convincing chord changes in minutes.
All twelve at a glance
| Major | Signature | Relative minor | Notes |
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