Aaug7: A Augmented 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♯	Minor sixth	8
♭7	G	Minor seventh	10

Construction

A Augmented 7th = Root + Major 3rd + Minor 6th + Minor 7th = A, C♯, E♯, G

Note	Interval	Degree
A	Root	1
C♯	Major 3rd	3
E♯	Minor 6th	♯5
G	Minor 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	white	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 Augmented 7th Inversions

Root position
A – C♯ – E♯ – G
1st inversion (Aaug7/C♯)
C♯ – E♯ – G – A
2nd inversion (Aaug7/E♯)
E♯ – G – A – C♯
3rd inversion (Aaug7/G)
G – A – C♯ – E♯

Key Signature

A Augmented 7th chord is built from symmetrical or ambiguous intervals, so it doesn't belong to a single key and has no key signature of its own.

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

Same Notes, Other Names

The notes A – C♯ – E♯ – G aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:

A 7♯5→

A Augmented 7th : Frequently Asked Questions

What notes are in Aaug7?

Aaug7 contains A, C♯, E♯ and G. The formula is 1, 3, ♯5, ♭7.

How do you play Aaug7 on piano?

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

What are the inversions of Aaug7?

4 positions: root position A C♯ E♯ G, Aaug7/C♯, Aaug7/E♯, Aaug7/G.

What is the difference between Aaug7 and Aaug?

Drops G. 3 of the notes are shared.

What is an easy Aaug7 for small hands?

The guide tones, 3 and ♭7 voicing, C♯4 G4, spans 6 semitones or about 83 mm.

What are the frequencies of Aaug7?

From A3 at A440 in 12-TET: 220.00, 277.18, 349.23, 392.00 Hz.

What is the set class of Aaug7?

Prime form (0248), Forte 4-24, interval vector <020301>.

How do I transpose Aaug7 to another key?

Keep the 1, 3, ♯5, ♭7 formula on the new root. Caug7 is C, E, G♯, B♭; D♭aug7 is D♭, F, A, C♭.

A Augmented 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 E♯4 G4	10	138 mm	none	identical
Close, first inversion	C♯4 E♯4 G4 A4	8	110 mm	none	identical
Close, second inversion	E♯4 G4 A4 C♯5	8	110 mm	none	identical
Close, third inversion	G4 A4 C♯5 E♯5	10	138 mm	none	identical
Drop 2	E♯3 A3 C♯4 G4	14	193 mm	none	identical
Drop 3	C♯3 A3 E♯4 G4	18	248 mm	none	identical
Drop 2 and 4	A2 E♯3 C♯4 G4	22	303 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 G3 C♯4	16	220 mm	omits E♯	subset
Guide tones, 3 and ♭7	C♯4 G4	6	83 mm	omits A and E♯	subset
Rootless close	C♯4 E♯4 G4	6	83 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, E♯4, G4	7	10	138 mm
First inversion: Aaug7/C♯	C♯	C♯4, E♯4, G4, A4	6/5	8	110 mm
Second inversion: Aaug7/E♯	E♯	E♯4, G4, A4, C♯5	4/3	8	110 mm
Third inversion: Aaug7/G	G	G4, A4, C♯5, E♯5	4/2	10	138 mm

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

Change one note

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

Chord	Change	Formula	Common tones
Aaug	drops G	1 3 ♯5	3
A7	E♯ becomes E	1 3 5 ♭7	3
A9	E♯ becomes E, B	1 3 5 ♭7 9	3
A	E♯, G becomes E	1 3 5	2
Amaj7	E♯, G becomes E, G♯	1 3 5 7	2
Am7	C♯, E♯ becomes C, E	1 ♭3 5 ♭7	2
Am7♭5	C♯, E♯ becomes C, E♭	1 ♭3 ♭5 ♭7	2
A7sus4	C♯, E♯ becomes D, E	1 4 5 ♭7	2
A6	E♯, G becomes E, F♯	1 3 5 6	2
Aadd9	E♯, G becomes E, B	1 3 5 9	2

Frequencies

Note	MIDI	Frequency
A3	57	220.00 Hz
C♯4	61	277.18 Hz
E♯4	65	349.23 Hz
G4	67	392.00 Hz

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

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {9, 1, 5, 7}
Normal order: [5, 7, 9, 1]
Prime form: (0248)
Forte number: 4-24
Interval vector: <020301>

Pair	Interval	Semitones	Interval class
A to C♯	Major third	4	4
A to E♯	Minor sixth	8	4
A to G	Minor seventh	10	2
C♯ to E♯	Major third	4	4
C♯ to G	Tritone	6	6
E♯ to G	Major second	2	2

Where these facts come from

Every value on this page is derived from the note formula for a augmented 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 Augmented 7th

Fingerings

A Augmented 7th: notes and degrees