# A Augmented piano chord (Aaug)

Aaug contains A, C♯ and E♯. Two stacked major thirds. C♯ is a black key; A and E♯ are white.

- Canonical page: https://piano.org/chords/augmented/a/
- Entity: chord:augmented:a
- Notes: A C♯ E♯
- Formula: 1 3 ♯5
- Intervals from root: P1, M3, m6
- Interval stack (semitones): 4 4
- Also written: Aaug, Aaug, A augmented
- Parameters: A440, 12-TET, 165 mm octave, spans centre to centre

## Construction

| Degree | Note | Interval from root | Semitones |
| --- | --- | --- | --- |
| 1 | A | Perfect unison | 0 |
| 3 | C♯ | Major third | 4 |
| ♯5 | E♯ | Minor sixth | 8 |

## Fingering

Rest your right hand over the notes with finger 1 on A, finger 3 on C♯, finger 5 on E♯. The left hand mirrors it.
Right hand 1-3-5, left hand 5-3-1. Source: piano.org fingering method v1.

## Inversions

| Position | Bass | Notes in order | Figured bass | Span |
| --- | --- | --- | --- | --- |
| Root position | A | A3 C♯4 E♯4 | 5/3 | 8 st, 110 mm |
| First inversion (Aaug/C♯) | C♯ | C♯4 E♯4 A4 | 6/3 | 8 st, 110 mm |
| Second inversion (Aaug/E♯) | E♯ | E♯4 A4 C♯5 | 6/4 | 8 st, 110 mm |

## Voicings (5)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | A3 C♯4 E♯4 | 8 st, 110 mm | identical | none |
| Close, first inversion | C♯4 E♯4 A4 | 8 st, 110 mm | identical | none |
| Close, second inversion | E♯4 A4 C♯5 | 8 st, 110 mm | identical | none |
| Open, fifth on top | A2 E♯3 C♯4 | 16 st, 220 mm | identical | none |
| Root and third only | A3 C♯4 | 4 st, 55 mm | subset | omits E♯ |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| Aaug7 | 1 3 ♯5 ♭7 | adds G | 3 |
| A | 1 3 5 | E♯ becomes E | 2 |
| Amaj7 | 1 3 5 7 | E♯ becomes E, G♯ | 2 |
| A7 | 1 3 5 ♭7 | E♯ becomes E, G | 2 |
| A6 | 1 3 5 6 | E♯ becomes E, F♯ | 2 |
| Aadd9 | 1 3 5 9 | E♯ becomes E, B | 2 |
| Am | 1 ♭3 5 | C♯, E♯ becomes C, E | 1 |
| Adim | 1 ♭3 ♭5 | C♯, E♯ becomes C, E♭ | 1 |
| Asus2 | 1 2 5 | C♯, E♯ becomes B, E | 1 |
| Asus4 | 1 4 5 | C♯, E♯ becomes D, E | 1 |

## Set theory

- Absolute pitch classes: {9, 1, 5}
- Relative pitch classes: [0, 4, 8]
- Normal order: [1, 5, 9]
- Prime form: (048)
- Forte number: 3-12
- Interval vector: <000300>

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| A3 | 57 | 220.00 Hz |
| C♯4 | 61 | 277.18 Hz |
| E♯4 | 65 | 349.23 Hz |

## Questions and answers

### What notes are in Aaug?

Aaug contains A, C♯ and E♯. The formula is 1, 3, ♯5.

### How do you play Aaug on piano?

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

### What are the inversions of Aaug?

3 positions: root position A C♯ E♯, Aaug/C♯, Aaug/E♯.

### What is the difference between Aaug and Aaug7?

Adds G. 3 of the notes are shared.

### What is an easy Aaug for small hands?

The root and third only voicing, A3 C♯4, spans 4 semitones or about 55 mm.

### What are the frequencies of Aaug?

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

### What is the set class of Aaug?

Prime form (048), Forte 3-12, interval vector &lt;000300&gt;.

### How do I transpose Aaug to another key?

Keep the 1, 3, ♯5 formula on the new root. Caug is C, E, G♯; D♭aug is D♭, F, A.

## Provenance

Every derived value above is computed by the piano.org theory kernel from the root, the quality and the stated parameters. Nothing is hand-entered per chord.

Machine record: https://piano.org/api/knowledge/v1/entities/chord:augmented:a
Last reviewed: 2026-08-12