# C Augmented 7th piano chord (Caug7)

Caug7 contains C, E, G♯ and B♭. An augmented triad with the minor seventh added on top. G♯ and B♭ are black keys; C and E are white.

- Canonical page: https://piano.org/chords/augmented-7th/c/
- Entity: chord:augmented-7th:c
- Notes: C E G♯ B♭
- Formula: 1 3 ♯5 ♭7
- Intervals from root: P1, M3, m6, m7
- Interval stack (semitones): 4 4 2
- Also written: Caug7, Caug7, C augmented 7th
- 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 |
| ♭7 | B♭ | Minor seventh | 10 |

## Fingering

Rest your right hand over the notes with finger 1 on C, finger 2 on E, finger 3 on G♯, finger 5 on B♭. The left hand mirrors it.
Right hand 1-2-3-5, left hand 5-3-2-1. Source: piano.org fingering method v1.

## Inversions

| Position | Bass | Notes in order | Figured bass | Span |
| --- | --- | --- | --- | --- |
| Root position | C | C3 E3 G♯3 B♭3 | 7 | 10 st, 138 mm |
| First inversion (Caug7/E) | E | E3 G♯3 B♭3 C4 | 6/5 | 8 st, 110 mm |
| Second inversion (Caug7/G♯) | G♯ | G♯3 B♭3 C4 E4 | 4/3 | 8 st, 110 mm |
| Third inversion (Caug7/B♭) | B♭ | B♭3 C4 E4 G♯4 | 4/2 | 10 st, 138 mm |

## Voicings (10)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | C3 E3 G♯3 B♭3 | 10 st, 138 mm | identical | none |
| Close, first inversion | E3 G♯3 B♭3 C4 | 8 st, 110 mm | identical | none |
| Close, second inversion | G♯3 B♭3 C4 E4 | 8 st, 110 mm | identical | none |
| Close, third inversion | B♭3 C4 E4 G♯4 | 10 st, 138 mm | identical | none |
| Drop 2 | G♯2 C3 E3 B♭3 | 14 st, 193 mm | identical | none |
| Drop 3 | E2 C3 G♯3 B♭3 | 18 st, 248 mm | identical | none |
| Drop 2 and 4 | C2 G♯2 E3 B♭3 | 22 st, 303 mm | identical | none |
| Shell, root ♭7 3 | C2 B♭2 E3 | 16 st, 220 mm | subset | omits G♯ |
| Guide tones, 3 and ♭7 | E3 B♭3 | 6 st, 83 mm | subset | omits C and G♯ |
| Rootless close | E3 G♯3 B♭3 | 6 st, 83 mm | subset | omits C |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| Caug | 1 3 ♯5 | drops B♭ | 3 |
| C7 | 1 3 5 ♭7 | G♯ becomes G | 3 |
| C9 | 1 3 5 ♭7 9 | G♯ becomes G, D | 3 |
| C | 1 3 5 | G♯, B♭ becomes G | 2 |
| Cmaj7 | 1 3 5 7 | G♯, B♭ becomes G, B | 2 |
| Cm7 | 1 ♭3 5 ♭7 | E, G♯ becomes E♭, G | 2 |
| Cm7♭5 | 1 ♭3 ♭5 ♭7 | E, G♯ becomes E♭, G♭ | 2 |
| C7sus4 | 1 4 5 ♭7 | E, G♯ becomes F, G | 2 |
| C6 | 1 3 5 6 | G♯, B♭ becomes G, A | 2 |
| Cadd9 | 1 3 5 9 | G♯, B♭ becomes G, D | 2 |

## Set theory

- Absolute pitch classes: {0, 4, 8, 10}
- Relative pitch classes: [0, 4, 8, 10]
- Normal order: [8, 10, 0, 4]
- Prime form: (0248)
- Forte number: 4-24
- Interval vector: <020301>

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| C3 | 48 | 130.81 Hz |
| E3 | 52 | 164.81 Hz |
| G♯3 | 56 | 207.65 Hz |
| B♭3 | 58 | 233.08 Hz |

## Questions and answers

### What notes are in Caug7?

Caug7 contains C, E, G♯ and B♭. The formula is 1, 3, ♯5, ♭7.

### How do you play Caug7 on piano?

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

### What are the inversions of Caug7?

4 positions: root position C E G♯ B♭, Caug7/E, Caug7/G♯, Caug7/B♭.

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

Drops B♭. 3 of the notes are shared.

### What is an easy Caug7 for small hands?

The guide tones, 3 and ♭7 voicing, E3 B♭3, spans 6 semitones or about 83 mm.

### What are the frequencies of Caug7?

From C3 at A440 in 12-TET: 130.81, 164.81, 207.65, 233.08 Hz.

### What is the set class of Caug7?

Prime form (0248), Forte 4-24, interval vector &lt;020301&gt;.

### How do I transpose Caug7 to another key?

Keep the 1, 3, ♯5, ♭7 formula on the new root. D♭aug7 is D♭, F, A, C♭; Daug7 is D, F♯, A♯, C.

## 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-7th:c
Last reviewed: 2026-08-12