# C Augmented piano chord (Caug)

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

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

## Construction

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

## Fingering

Rest your right hand over the notes with finger 1 on C, finger 3 on E, finger 5 on G♯. 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 | C | C3 E3 G♯3 | 5/3 | 8 st, 110 mm |
| First inversion (Caug/E) | E | E3 G♯3 C4 | 6/3 | 8 st, 110 mm |
| Second inversion (Caug/G♯) | G♯ | G♯3 C4 E4 | 6/4 | 8 st, 110 mm |

## Voicings (5)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | C3 E3 G♯3 | 8 st, 110 mm | identical | none |
| Close, first inversion | E3 G♯3 C4 | 8 st, 110 mm | identical | none |
| Close, second inversion | G♯3 C4 E4 | 8 st, 110 mm | identical | none |
| Open, fifth on top | C2 G♯2 E3 | 16 st, 220 mm | identical | none |
| Root and third only | C3 E3 | 4 st, 55 mm | subset | omits G♯ |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| Caug7 | 1 3 ♯5 ♭7 | adds B♭ | 3 |
| C | 1 3 5 | G♯ becomes G | 2 |
| Cmaj7 | 1 3 5 7 | G♯ becomes G, B | 2 |
| C7 | 1 3 5 ♭7 | G♯ becomes G, B♭ | 2 |
| C6 | 1 3 5 6 | G♯ becomes G, A | 2 |
| Cadd9 | 1 3 5 9 | G♯ becomes G, D | 2 |
| Cm | 1 ♭3 5 | E, G♯ becomes E♭, G | 1 |
| Cdim | 1 ♭3 ♭5 | E, G♯ becomes E♭, G♭ | 1 |
| Csus2 | 1 2 5 | E, G♯ becomes D, G | 1 |
| Csus4 | 1 4 5 | E, G♯ becomes F, G | 1 |

## Set theory

- Absolute pitch classes: {0, 4, 8}
- 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 |
| --- | --- | --- |
| C3 | 48 | 130.81 Hz |
| E3 | 52 | 164.81 Hz |
| G♯3 | 56 | 207.65 Hz |

## Questions and answers

### What notes are in Caug?

Caug contains C, E and G♯. The formula is 1, 3, ♯5.

### How do you play Caug on piano?

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

### What are the inversions of Caug?

3 positions: root position C E G♯, Caug/E, Caug/G♯.

### What is the difference between Caug and Caug7?

Adds B♭. 3 of the notes are shared.

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

The root and third only voicing, C3 E3, spans 4 semitones or about 55 mm.

### What are the frequencies of Caug?

From C3 at A440 in 12-TET: 130.81, 164.81, 207.65 Hz.

### What is the set class of Caug?

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

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

Keep the 1, 3, ♯5 formula on the new root. D♭aug is D♭, F, A; Daug 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:c
Last reviewed: 2026-08-12