Key reference

The key of A major

3 sharps · A – B – C♯ – D – E – F♯ – G♯

A major has 3 sharps: F♯, C♯, G♯. A piece in this key draws on A, B, C♯, D, E, F♯, G♯ and treats A as home.

The seven chords below are the ones built from those notes alone, which is why they sound like they belong together.

The key signature

The key signature of A major: F, C, G.

Order of sharps

F♯
C♯
G♯
D♯
A♯
E♯
B♯

This signature uses the first 3 of them: F♯, C♯, G♯.

The notes of the key

These are the notes of the major scale on this tonic. See the A major scale for the degrees and step pattern.

A – B – C♯ – D – E – F♯ – G♯

The seven diatonic chords

Build a triad on each degree using only notes from the key and the qualities fall into a fixed pattern. That pattern is the same in every major key, which is why progressions transpose so cleanly.

Degree	Roman	Chord	Notes	Function
1	I	A	A – C♯ – E	Tonic
2	ii	Bm	B – D – F♯	Predominant
3	iii	C♯m	C♯ – E – G♯	Tonic
4	IV	D	D – F♯ – A	Predominant
5	V	E	E – G♯ – B	Dominant
6	vi	F♯m	F♯ – A – C♯	Tonic
7	vii°	G♯dim	G♯ – B – D	Dominant

Adding sevenths

Stack one more third on each and you get the seventh chords of the key.

Roman	Chord	Notes
I	Amaj7	A – C♯ – E – G♯
ii	Bm7	B – D – F♯ – A
iii	C♯m7	C♯ – E – G♯ – B
IV	Dmaj7	D – F♯ – A – C♯
V7	E7	E – G♯ – B – D
vi	F♯m7	F♯ – A – C♯ – E
vii°	G♯m7♭5	G♯ – B – D – F♯

Common progressions in A major

These are the same shapes you meet in every major key, written with this key’s chords.

I – V – vi – IV

AITonic
EVDominant
F♯mviTonic
DIVPredominant

I – vi – IV – V

AITonic
F♯mviTonic
DIVPredominant
EVDominant

ii – V – I

BmiiPredominant
EVDominant
AITonic

Related keys

Relationship	Key	Signature
Relative minor	F♯ minor	Same signature
Parallel minor	A minor	0 sharps
One step sharpwards	E major	One more sharp
One step flatwards	D major	One more flat

Neighbouring keys on the circle of fifths share six of their seven notes.