# A♭ Augmented piano chord (A♭aug)

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

- Canonical page: https://piano.org/chords/augmented/a-flat/
- Entity: chord:augmented:a-flat
- Notes: A♭ C E
- Formula: 1 3 ♯5
- Intervals from root: P1, M3, m6
- Interval stack (semitones): 4 4
- Also written: A♭aug, Abaug, 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♭ | A♭3 C4 E4 | 5/3 | 8 st, 110 mm |
| First inversion (A♭aug/C) | C | C4 E4 A♭4 | 6/3 | 8 st, 110 mm |
| Second inversion (A♭aug/E) | E | E4 A♭4 C5 | 6/4 | 8 st, 110 mm |

## Voicings (5)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | A♭3 C4 E4 | 8 st, 110 mm | identical | none |
| Close, first inversion | C4 E4 A♭4 | 8 st, 110 mm | identical | none |
| Close, second inversion | E4 A♭4 C5 | 8 st, 110 mm | identical | none |
| Open, fifth on top | A♭2 E3 C4 | 16 st, 220 mm | identical | none |
| Root and third only | A♭3 C4 | 4 st, 55 mm | subset | omits E |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| A♭aug7 | 1 3 ♯5 ♭7 | adds G♭ | 3 |
| A♭ | 1 3 5 | E becomes E♭ | 2 |
| A♭maj7 | 1 3 5 7 | E becomes E♭, G | 2 |
| A♭7 | 1 3 5 ♭7 | E becomes E♭, G♭ | 2 |
| A♭6 | 1 3 5 6 | E becomes E♭, F | 2 |
| A♭add9 | 1 3 5 9 | E becomes E♭, B♭ | 2 |
| A♭m | 1 ♭3 5 | C, E becomes C♭, E♭ | 1 |
| A♭dim | 1 ♭3 ♭5 | C, E becomes C♭, E♭♭ | 1 |
| A♭sus2 | 1 2 5 | C, E becomes B♭, E♭ | 1 |
| A♭sus4 | 1 4 5 | C, E becomes D♭, E♭ | 1 |

## Set theory

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

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| A♭3 | 56 | 207.65 Hz |
| C4 | 60 | 261.63 Hz |
| E4 | 64 | 329.63 Hz |

## Questions and answers

### What notes are in A♭aug?

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

### How do you play A♭aug on piano?

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

### What are the inversions of A♭aug?

3 positions: root position A♭ C E, A♭aug/C, A♭aug/E.

### What is the difference between A♭aug and A♭aug7?

Adds G♭. 3 of the notes are shared.

### What is an easy A♭aug for small hands?

The root and third only voicing, A♭3 C4, spans 4 semitones or about 55 mm.

### What are the frequencies of A♭aug?

From A♭3 at A440 in 12-TET: 207.65, 261.63, 329.63 Hz.

### What is the set class of A♭aug?

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

### How do I transpose A♭aug to another key?

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

### Is G♯aug the same as A♭aug?

Enharmonically yes: the same piano keys and the same sound, spelled differently.

## 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-flat
Last reviewed: 2026-08-12