Twelve major keys, their relative minors, the diatonic chords with Roman numerals, and the seven modes ordered brightest to darkest.
The circle of fifths is the single most useful diagram in Western music. It arranges all twelve major keys in a ring so that the ones which sound closely related sit next to each other — and once you can read it, it answers a surprising number of everyday questions at a glance: how many sharps or flats a key has, which minor key it shares them with, which chords belong together, and where a piece can comfortably move next.
For three hundred years it lived on a page — a fixed chart to memorise. Here it turns. Set any key at the centre, change the mode, and watch the chords and Roman numerals rearrange themselves around it.
Start at C at the top and move one step clockwise: you land on G. Another step: D, then A, and so on. Each move is a perfect fifth — five letter-names up the scale (C‑D‑E‑F‑G). Keep going and, after twelve steps, you arrive back at C. That is the whole idea: twelve fifths, laid end to end, close into a circle.
The arrangement is not decorative. Neighbouring keys are among the most closely related keys in music — they share every note but one. That single-note difference is why moving between them sounds smooth, and it is the reason the circle is such a practical map.
Adjacent keys share six of their seven notes. Keys on opposite sides share almost none.
The Circle of Fifths03
GressusReading the circle
How to read it
There are two directions, and each has a meaning:
Clockwise ↻
Up a perfect fifth each step (C → G → D → A …). Every step adds one sharp. The keys on the right-hand side are the sharp keys.
Anticlockwise ↺
Up a perfect fourth each step (C → F → B♭ → E♭ …). Every step adds one flat. The keys on the left-hand side are the flat keys.
At the bottom of the circle the two sides meet, and the same pitch is spelled two ways — F♯ major and G♭ major are the same key on a keyboard, written differently. These are enharmonic equivalents.
Because each step changes only one note, the further apart two keys are on the circle, the more their notes differ — and the more distant they sound.
The Circle of Fifths04
GressusKey signatures
Key signatures at a glance
The circle is the fastest way to recall any key signature. Walking clockwise adds sharps one at a time, always in the same order; walking anticlockwise adds flats in the reverse order.
Mnemonics
Order of sharps
F♯ C♯ G♯ D♯ A♯ E♯ B♯
Father Charles Goes Down And Ends Battle
Order of flats
B♭ E♭ A♭ D♭ G♭ C♭ F♭
Battle Ends And Down Goes Charles' Father
Table 1 · Sharp keys, clockwise from C
Key
Sharps
Which sharps
major
0
—
major
1
F♯
major
2
F♯ C♯
major
3
F♯ C♯ G♯
major
4
F♯ C♯ G♯ D♯
major
5
F♯ C♯ G♯ D♯ A♯
major
6
F♯ C♯ G♯ D♯ A♯ E♯
major
7
F♯ C♯ G♯ D♯ A♯ E♯ B♯
The Circle of Fifths05
GressusKey signatures
Table 2 · Flat keys, anticlockwise from C
Key
Flats
Which flats
major
0
—
major
1
B♭
major
2
B♭ E♭
major
3
B♭ E♭ A♭
major
4
B♭ E♭ A♭ D♭
major
5
B♭ E♭ A♭ D♭ G♭
major
6
B♭ E♭ A♭ D♭ G♭ C♭
major
7
B♭ E♭ A♭ D♭ G♭ C♭ F♭
Two quick tricks
1
In a sharp key, the last sharp is a semitone below the key note — if the last sharp is G♯, the key is A.
2
In a flat key, the second-to-last flat is the key note — if the flats are B♭ E♭ A♭ D♭, the key is A♭ (except F major, which has only one flat).
The Circle of Fifths06
GressusRelative minors
Relative minors
Every major key shares its key signature with one minor key — its relative minor. They use exactly the same notes; they simply treat a different note as home. The relative minor starts on the sixth degree of the major scale, which is three semitones below the major key note (A is the relative minor of C).
On the wheel, the relative minors form the next ring out from the majors — each sits directly outside its own major — with the diminished chords on the ring beyond.
Table 3 · Relative minors
Major key
Relative minor
Shared signature
none
1♯
2♯
3♯
4♯
5♯
6♯
7♯
1♭
2♭
3♭
4♭
5♭
6♭
7♭
The Circle of Fifths07
GressusModes
The modes around the wheel
A mode is what you get by taking the seven notes of a key but treating a different note as home. Because the circle is already ordered by brightness — sharps to the right, flats to the left — it also orders the seven modes, from the brightest to the darkest.
Table 4 · The modes, brightest to darkest
Mode
Character
Vs the major scale
Lydian
brightest
♯4
Ionian
the major scale
—
Mixolydian
major, bluesy
♭7
Dorian
warm minor
♭3 ♭7
Aeolian
the natural minor scale
♭3 ♭6 ♭7
Phrygian
dark minor
♭2 ♭3 ♭6 ♭7
Locrian
darkest, unsettled
♭2 ♭3 ♭5 ♭6 ♭7
Reading top to bottom, each mode flattens one more note than the last. Lydian raises the fourth and is the brightest; Locrian flattens almost everything and barely feels like a home key at all. Set a mode on the wheel and the chords and numerals shift to match it. The Fretboard Visualiser has all the modes on the neck.
The Circle of Fifths08
GressusDiatonic chords
The chords in a major key
Build a three-note chord on each degree of a major scale, using only that key's notes, and you get a fixed pattern of qualities — the same shape in every key. This is why the same chords keep company: they are simply the chords the key contains — its diatonic chords. Taking C major as the example:
Table 5 · Diatonic chords in C major
Degree
Chord
Quality
Roman
1
major
I
2
minor
ii
3
minor
iii
4
major
IV
5
major
V
6
minor
vi
7
diminished
vii°
That pattern of qualities — major, minor, minor, major, major, minor, diminished — is the same in every major key, and the Roman numerals encode it: a capital numeral is a major chord (I, IV, V), a lower-case one is minor (ii, iii, vi), and the lower-case numeral with a ° is the diminished chord (vii°).
So I, IV and V — the tonic and its two neighbours a fifth away — are the bright major chords; ii, iii and vi are their relative minors; and vii° is the single restless diminished chord. The wheel shows all seven live: choose a key and its diatonic chords light up, each with its numeral. The Chord Library builds each one, note by note.
The Circle of Fifths09
GressusDiatonic chords
The chords in a minor key
A minor key has its own diatonic set. A minor — the relative minor of C — draws on the very same seven chords, but now A minor is home, so the pattern of qualities starts in a different place. Taking A minor:
Table 6 · Diatonic chords in A minor
Degree
Chord
Quality
Roman
1
minor
i
2
diminished
ii°
3
major
III
4
minor
iv
5
minor
v
6
major
VI
7
major
VII
The order runs minor, diminished, major, minor, minor, major, major — i, ii°, III, iv, v, VI, VII. The tonic (i), subdominant (iv) and dominant (v) are the minor chords; III, VI and VII are the majors; and ii° is the lone diminished chord.
Because A minor and C major share their notes, they share these seven chords — the wheel's wedge covers both keys at once; only the numbering changes.
In practice, music in a minor key usually raises its seventh note — G to G♯ in A minor. That turns the minor v into a major V (E major), which pulls far more strongly towards home. The raised seventh is the harmonic minor scale, set out on the scale pages.
The Circle of Fifths10
GressusIn practice
How musicians actually use it
Finding related keys and modulating
The neighbours of any key are its closest relations, so a move to an adjacent key sounds natural. Composers use the circle to plan where a piece travels.
Building chord progressions
Many of the strongest progressions are simply moves around the circle — the ii–V–I that underpins most jazz is two adjacent steps.
Transposing
Because the seven positions never move, the wheel transposes for you: learn a song as its numerals (say I–V–vi–IV), point the wheel at a new key, and read the chords straight off the same positions — same shape, new key.
Sight-reading and improvising
Knowing a key's signature and its diatonic chords on sight is most of the battle — and both are readable straight from the circle.
The Circle of Fifths11
GressusFAQ
Frequently asked questions
Why is it called the circle of fifths?
Because each clockwise step is a perfect fifth. Twelve fifths in a row pass through all twelve notes and return to the start, closing the line into a circle.
How do you memorise it?
Learn the clockwise order — C G D A E B F♯ … — and the order of sharps (Father Charles Goes Down And Ends Battle). The flats are the same names reversed.
Sharps or flats — how do I know which?
Right-hand (clockwise) keys use sharps; left-hand (anticlockwise) keys use flats. At the bottom the two meet — F♯ and G♭ are the same notes, spelled differently.
What is a relative minor?
The minor key that shares a major key's exact notes and signature, starting three semitones lower (A minor for C major). Same notes, different home.
Do I have to learn all twelve keys?
Not at once. Most players start with the keys nearest C — G, D, F, B♭ — and let the rest come with time. The pattern is identical in every key, so learning one teaches you all of them.
The Circle of Fifths12
TOM · Teacher Of Music
The old textbook, brought to life.
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