Amaj7: A Major 7th Piano Chord

Root position: either hand, fingers low note to high
Hand	Notes	Fingers
Right	A, C♯, E, G♯	1-2-3-5
Left	A, C♯, E, G♯	5-3-2-1

Scale degree, note, and interval measured from the root.
Degree	Note	Interval from root	Semitones
1	A	Perfect unison	0
3	C♯	Major third	4
5	E	Perfect fifth	7
7	G♯	Major seventh	11

Construction

A Major 7th = Root + Major 3rd + Perfect 5th + Major 7th = A, C♯, E, G♯

Note	Interval	Degree
A	Root	1
C♯	Major 3rd	3
E	Perfect 5th	5
G♯	Major 7th	7

Fingering

Note	Key color	Right hand	Left hand
A	white	thumb (1)	little finger (5)
C♯	black	index finger (2)	middle finger (3)
E	white	middle finger (3)	index finger (2)
G♯	black	little finger (5)	thumb (1)

Right hand: thumb (1) on A, index finger (2) on C♯, middle finger (3) on E, little finger (5) on G♯.

Left hand: little finger (5) on A, middle finger (3) on C♯, index finger (2) on E, thumb (1) on G♯.

A Major 7th Inversions

Root position
A – C♯ – E – G♯
1st inversion (Amaj7/C♯)
C♯ – E – G♯ – A
2nd inversion (Amaj7/E)
E – G♯ – A – C♯
3rd inversion (Amaj7/G♯)
G♯ – A – C♯ – E

Key Signature

A chord has no key signature of its own, but the A Major 7th is the tonic (I) chord of A Major, whose key signature has 3 sharps (F♯, C♯, G♯).

F♯C♯G♯

Order of sharps

Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.

F♯C♯G♯D♯A♯E♯B♯

Mnemonic: Father Charles Goes Down And Ends Battle

Chords in the Key of A Major

These are the triads built on each degree of A Major:

I — A Major (major)

Degree	Numeral	Chord	Quality
1	I	A Major	Major
2	ii	B Minor	Minor
3	iii	C♯ Minor	Minor
4	IV	D Major	Major
5	V	E Major	Major
6	vi	F♯ Minor	Minor
7	vii°	G♯ Diminished	Diminished

How A Major 7th functions in a key

The same chord takes on a different harmonic role depending on the key it appears in. Here is where A Major 7th sits diatonically across the common keys:

In A major, A Major 7th is the I chord — the tonic.
In C♯ minor, A Major 7th is the VI chord — the tonic.
In E major, A Major 7th is the IV chord — a predominant.
In F♯ minor, A Major 7th is the III chord — a mediant / color chord.

Scales That Include the A Major 7th

A Major (Imaj7)
E Major (IVmaj7)
F# Minor (♭IIImaj7)
C# Minor (♭VImaj7)
B Dorian (VII)
C# Phrygian (VI)
D Lydian (V)
E Mixolydian (IV)

A Major 7th : Frequently Asked Questions

What notes are in Amaj7?

Amaj7 contains A, C♯, E and G♯. The formula is 1, 3, 5, 7.

How do you play Amaj7 on piano?

Play A, C♯, E and G♯ together. Right hand fingers 1, 2, 3, 5; left hand 5, 3, 2, 1. C♯ and G♯ are black keys; A and E are white.

What are the inversions of Amaj7?

4 positions: root position A C♯ E G♯, Amaj7/C♯, Amaj7/E, Amaj7/G♯.

What keys contain Amaj7?

4: ♭VImaj7 in C♯ minor, IVmaj7 in E major, ♭IIImaj7 in F♯ minor, Imaj7 in A major.

What is the difference between Amaj7 and Amaj9?

Adds B. 4 of the notes are shared.

What is an easy Amaj7 for small hands?

The guide tones, 3 and 7 voicing, C♯4 G♯4, spans 7 semitones or about 96 mm.

What are the frequencies of Amaj7?

From A3 at A440 in 12-TET: 220.00, 277.18, 329.63, 415.30 Hz.

What is the set class of Amaj7?

Prime form (0158), Forte 4-20, interval vector <101220>.

How do I transpose Amaj7 to another key?

Keep the 1, 3, 5, 7 formula on the new root. Cmaj7 is C, E, G, B; C♯maj7 is C♯, E♯, G♯, B♯.

A Major 7th in detail

Exact

Every pitch class is present and nothing outside the chord is added.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Close, root position	A3 C♯4 E4 G♯4	11	151 mm	none	identical
Close, first inversion	C♯4 E4 G♯4 A4	8	110 mm	none	identical
Close, second inversion	E4 G♯4 A4 C♯5	9	124 mm	none	identical
Close, third inversion	G♯4 A4 C♯5 E5	8	110 mm	none	identical
Drop 2	E3 A3 C♯4 G♯4	16	220 mm	none	identical
Drop 3	C♯3 A3 E4 G♯4	19	261 mm	none	identical
Drop 2 and 4	A2 E3 C♯4 G♯4	23	316 mm	none	identical

Reduced

A subset of the pitch classes: the identity is incomplete rather than altered.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Shell, root 7 3	A2 G♯3 C♯4	16	220 mm	omits E	subset
Guide tones, 3 and 7	C♯4 G♯4	7	96 mm	omits A and E	subset
Rootless close	C♯4 E4 G♯4	7	96 mm	omits A	subset

Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).

Position	Bass note	Notes in order	Figured bass	Semitones	Span
Root position	A	A3, C♯4, E4, G♯4	7	11	151 mm
First inversion: Amaj7/C♯	C♯	C♯4, E4, G♯4, A4	6/5	8	110 mm
Second inversion: Amaj7/E	E	E4, G♯4, A4, C♯5	4/3	9	124 mm
Third inversion: Amaj7/G♯	G♯	G♯4, A4, C♯5, E5	4/2	8	110 mm

One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.

Progression	Key	Role	Sequence	Voice leading
♭VI, iv, i, v	C♯ minor	♭VImaj7	Amaj7 to F♯m7 to C♯m7 to G♯m7	Amaj7 opens the phrase
i, ♭VI	C♯ minor	♭VImaj7	C♯m7 to Amaj7	3 tones held from C♯m7
IV, V, I	E major	IVmaj7	Amaj7 to B7 to Emaj7	Amaj7 opens the phrase
I, IV	E major	IVmaj7	Emaj7 to Amaj7	2 tones held from Emaj7
♭III, ♭VI, ii, v	F♯ minor	♭IIImaj7	Amaj7 to Dmaj7 to G♯m7♭5 to C♯m7	Amaj7 opens the phrase
i, ♭III	F♯ minor	♭IIImaj7	F♯m7 to Amaj7	3 tones held from F♯m7
ii, V, I	A major	Imaj7	Bm7 to E7 to Amaj7	2 tones held from E7
IV, I	A major	Imaj7	Dmaj7 to Amaj7	2 tones held from Dmaj7
I, vi, ii, V	A major	Imaj7	Amaj7 to F♯m7 to Bm7 to E7	Amaj7 opens the phrase

Root motion, common tones and voice displacement are computed from pitch class sets. Roman numerals follow common practice functional harmony.

Which keys it belongs to

Key	Roman numeral	Function
C♯ minor	♭VImaj7	Pre-dominant color
E major	IVmaj7	Subdominant, away from home
F♯ minor	♭IIImaj7	Relative-major color
A major	Imaj7	Tonic, home

Classification system: common-practice functional harmony.

Change one note

Chords a single note away, and what moving that note does.

Chord	Change	Formula	Common tones
Amaj9	adds B	1 3 5 7 9	4
A	drops G♯	1 3 5	3
A7	G♯ becomes G	1 3 5 ♭7	3
AmMaj7	C♯ becomes C	1 ♭3 5 7	3
A6	G♯ becomes F♯	1 3 5 6	3
Aadd9	G♯ becomes B	1 3 5 9	3
A9	G♯ becomes G, B	1 3 5 ♭7 9	3
Am	C♯, G♯ becomes C	1 ♭3 5	2
Aaug	E, G♯ becomes E♯	1 3 ♯5	2
Asus2	C♯, G♯ becomes B	1 2 5	2
Asus4	C♯, G♯ becomes D	1 4 5	2
Am7	C♯, G♯ becomes C, G	1 ♭3 5 ♭7	2

Frequencies

Note	MIDI	Frequency
A3	57	220.00 Hz
C♯4	61	277.18 Hz
E4	64	329.63 Hz
G♯4	68	415.30 Hz

Reference pitch A440, 12-TET, close root position.

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {9, 1, 4, 8}
Normal order: [8, 9, 1, 4]
Prime form: (0158)
Forte number: 4-20
Interval vector: <101220>

Pair	Interval	Semitones	Interval class
A to C♯	Major third	4	4
A to E	Perfect fifth	7	5
A to G♯	Major seventh	11	1
C♯ to E	Minor third	3	3
C♯ to G♯	Perfect fifth	7	5
E to G♯	Major third	4	4

Where these facts come from

Every value on this page is derived from the note formula for a major 7th applied to the root A, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.

A Major 7th

Fingerings

A Major 7th: notes and degrees