The circle of fifths for guitarists: how to read it and use it

The circle of fifths is a diagram of the 12 major keys arranged so that each key is a perfect fifth above the previous one. Read clockwise from C at the top, it goes C, G, D, A, E, B, F#, then through the flat keys back to C. Each step clockwise adds one sharp to the key signature; each step counterclockwise adds one flat. The inner ring shows the relative minor of each key.

For a guitarist it is less a theory chart than a map: it tells you which chords belong together, how to move a song to a new key and where the strongest chord changes are. This guide shows you how to read it and how to use it with the chords you already play.

In short: clockwise steps go up a fifth and add a sharp, counterclockwise steps go up a fourth and add a flat. Any key's six main chords sit in a window of three neighbours: IV, I and V on the outer ring, ii, vi and iii on the inner ring below them. Transposing means rotating every chord by the same number of steps, and a secondary dominant is the major or 7th chord one step clockwise from the chord it resolves to.

What the circle of fifths is

A perfect fifth is an interval of 7 semitones: C to G, G to D, D to A. Stack twelve of them and you visit every note once before landing back on C (B to F# then continues as Gb, Db and so on, using enharmonic equivalents). That is why the diagram closes into a circle of fifths.

Going the other way, counterclockwise, each step is a perfect fourth up (5 semitones): C to F, F to Bb, Bb to Eb. A fourth up and a fifth down land on the same note name, which is why the same circle works in both directions.

The circle on the guitar neck

You already have the circle under your fingers. In standard tuning, the strings E, A, D and G are each a fourth apart. So at any fret:

• The same fret, one string toward the bass, is one step clockwise. A string 3rd fret is C; low E 3rd fret is G.
• The same fret, one string toward the treble, is one step counterclockwise. A string 3rd fret is C; D string 3rd fret is F; G string 3rd fret is Bb.
• Crossing from the G string to the B string, move up one fret, because that pair is tuned a major third apart. After Bb on the G string 3rd fret, the next step (Eb) is on the B string 4th fret.

Play the roots at the 3rd fret, low E to G string (G, C, F, Bb): you just walked four steps counterclockwise.

How to read key signatures with the circle

A key signature is the set of sharps and flats that a key uses. The circle gives them to you without memorising seven lists.

Major key	Relative minor	Signature	Sharps or flats
C	Am	none	none
G	Em	1 sharp	F#
D	Bm	2 sharps	F#, C#
A	F#m	3 sharps	F#, C#, G#
E	C#m	4 sharps	F#, C#, G#, D#
B	G#m	5 sharps	F#, C#, G#, D#, A#
F# / Gb	D#m / Ebm	6 sharps / 6 flats	F#, C#, G#, D#, A#, E# / Bb, Eb, Ab, Db, Gb, Cb
Db	Bbm	5 flats	Bb, Eb, Ab, Db, Gb
Ab	Fm	4 flats	Bb, Eb, Ab, Db
Eb	Cm	3 flats	Bb, Eb, Ab
Bb	Gm	2 flats	Bb, Eb
F	Dm	1 flat	Bb

Two rules make the table easy to rebuild:

1. Sharps are added in fifths too: F#, C#, G#, D#, A#, E#, B#. The new sharp is always the 7th note of the new key, one fret below its tonic. G major adds F#; D major adds C#.
2. Flats come in the reverse order: Bb, Eb, Ab, Db, Gb, Cb, Fb. In flat keys, the second-to-last flat names the key: three flats (Bb, Eb, Ab) means Eb major. F is the only one to learn by heart (one flat, Bb).

Notice what this means for guitar: the keys from C to E on the sharp side use the notes of our open strings, which is why most guitar songs live there.

Relative minors: the inner ring

Every major key shares its notes and key signature with one minor key, its relative minor. The relative minor starts on the 6th degree of the major scale, three frets (a minor third) below the major tonic.

On the guitar, find it in one move: from a major root on the low E or A string, go three frets down on the same string. G at the low E 3rd fret becomes E (open low E): G major and E minor. C at the A string 3rd fret becomes A (open A): C major and A minor. Same notes, different home.

That is why Am and C sound like family, and why a song in Em often borrows G, C and D.

How to find the 7 diatonic chords of any key

The diatonic chords are the seven chords built from the notes of a key. In every major key they follow the same pattern: I, ii, iii, IV, V, vi, vii°. The capital numerals are major, the lowercase ones minor, and vii° is a diminished chord.

The circle hands you six of them in one glance. Put your key at the top, then take a window of three neighbours:

• Outer ring: the key itself is I, its left neighbour (counterclockwise) is IV, its right neighbour (clockwise) is V.
• Inner ring: under IV, I and V you read ii, vi and iii.
• The 7th chord, vii°: the next minor one step further clockwise on the inner ring, played diminished.

For C: F, C, G on the outside; Dm, Am, Em on the inside; then B (from Bm) becomes Bdim. That gives C, Dm, Em, F, G, Am, Bdim. Move the window one step clockwise and you get the chords of G.

Key	I	ii	iii	IV	V	vi	vii°
C	C	Dm	Em	F	G	Am	Bdim
G	G	Am	Bm	C	D	Em	F#dim
D	D	Em	F#m	G	A	Bm	C#dim
A	A	Bm	C#m	D	E	F#m	G#dim
E	E	F#m	G#m	A	B	C#m	D#dim
F	F	Gm	Am	Bb	C	Dm	Edim

For guitar, the most comfortable keys are G and D. In G, the I, IV, V and vi (G, C, D, Em) are all open chords; in D, only the vi (Bm) needs a barre. If the eight open chords are still new to you, start with the 8 beginner chords first.

Using the circle to write progressions

The circle is also a map of how chords like to move.

Neighbours sound smooth

Chords that sit next to each other share notes and sound natural together. I, IV and V are neighbours, which is why I-IV-V (G-C-D in G) powers so much folk and rock. Staying inside the three-key window keeps you diatonic.

Counterclockwise is the strongest move

A root moving down a fifth (one step counterclockwise) is the strongest resolution in tonal music: V to I, G to C. Chain several and you get the classic circle progression:

• vi-ii-V-I: Am-Dm-G-C in C, Em-Am-D-G in G. Every step goes one notch counterclockwise.
• ii-V-I: Dm-G-C, the backbone of jazz and many pop bridges.

Any time you want a section to sound like it is "coming home", walk counterclockwise toward I. These cadences are easier to talk about in Roman numeral analysis: I, IV and V mean the same function in every key.

Changing key smoothly

Neighbouring keys differ by one sharp or flat. G and D share six of their seven notes, so a modulation from G to D (or C to G) sounds natural, while a jump from C to F# (opposite sides) sounds abrupt. Want a lift for the last chorus? Move one step clockwise.

Transposing with the circle (and a capo)

To transpose, rotate. Count how many steps clockwise the new key is, then move every chord by the same number of steps, keeping major chords on the outer ring and minor chords on the inner ring.

From G to A is two steps clockwise (G, D, A). So:

In G	Two steps clockwise	In A
G	G, D, A	A
D	D, A, E	E
Em	Em, Bm, F#m	F#m
C	C, G, D	D

G-D-Em-C becomes A-E-F#m-D. If F#m is a problem, keep the easy G shapes and put a capo on the 2nd fret: it raises everything by two semitones, from G to A. The songbook in the workshop transposes a whole chord sheet in one click, but knowing the rotation lets you do it on the spot.

Spotting secondary dominants

A secondary dominant is the dominant chord of a chord other than I. It is the chord one step clockwise from its target, played major, usually as a dominant seventh. It borrows a note from outside the key and pulls strongly toward its target.

In C major:

Target	One step clockwise	Secondary dominant	Open shape
Dm (ii)	A	A7 (V of ii)	x02020
Em (iii)	B	B7 (V of iii)	x21202
F (IV)	C	C7 (V of IV)	x32310
G (V)	D	D7 (V of V)	xx0212
Am (vi)	E	E7 (V of vi)	020100

How to spot one in a song: a major or 7th chord that does not belong to the key, followed by a chord one step counterclockwise. In C-A7-Dm-G7-C, the A7 contains C#, not in C major, and resolves to Dm: V of ii. In C-E7-Am, the E7 (with G#) pulls to Am.

Try it: in G, play G-E7-Am-D7-G. E7 is V of Am, D7 is V of G. Then try C-C7-F: the Bb in C7 turns C into a doorway to F. The chord substitutions tool (Premium or one-off module) lists the secondary dominants of any progression with playable voicings.

Explore the circle interactively

Reading the circle on paper is a good start; turning it is better. The interactive circle of fifths shows every key's signature, relative minor, diatonic chords and neighbours as you click, free with a GuitarHarmony account. When you are ready to write your own songs with it, browse the chord progressions of each style and transpose them around the circle.