C augmented chord (Caug)

The C augmented chord (Caug) is an augmented triad: C, E and G♯, two major thirds stacked on top of each other (root, major third and augmented fifth).

Because it splits the octave into three equal major thirds, C augmented has the same notes as E augmented; only the bass note changes.

With C, E and G♯, C augmented does not fit any major or natural minor scale: it is the chord on the third degree (III+) of the harmonic minor scale and is mostly used as a passing chord, as in I–I+–IV.

Below: voicings, notes on the fretboard, ukulele, piano and inversions.

How to play C augmented on guitar

There are 2 guitar voicings.

Frets from the 6th string to the 1st: x = not played, 0 = open string.

  • Voicing 1: x-3-2-1-1-0, open position, with C in the bass (fingers x-4-3-2-1-0).
  • Voicing 2: 8-x-10-9-9-x, with C in the bass (fingers 1-x-4-2-3-x).

Notes of the C augmented chord on the fretboard

C augmented has 3 notes: C, E and G♯. This is where they fall on each string, from the nut to the 12th fret (fret number in parentheses):

  • String 6 (E): E (0) · G♯ (4) · C (8) · E (12)
  • String 5 (A): C (3) · E (7) · G♯ (11)
  • String 4 (D): E (2) · G♯ (6) · C (10)
  • String 3 (G): G♯ (1) · C (5) · E (9)
  • String 2 (B): C (1) · E (5) · G♯ (9)
  • String 1 (E): E (0) · G♯ (4) · C (8) · E (12)

Formula and intervals of C augmented

Its formula is 1-3-♯5; in semitones from the root, 0-4-8.

  • C: Root, the note that gives the chord its name
  • E: Major third (M3), 4 semitones above C
  • G♯: Augmented fifth (A5), 8 semitones above C

C augmented on ukulele

  • Ukulele (G C E A): 1-0-0-3; it sounds G♯, C, E and C.

C augmented on piano

  • Keys: C4, E4 and G♯4.

Inversions of C augmented

Each inversion puts a different note in the bass.

  • Root position: C, E and G♯, with C in the bass.
  • First inversion (Caug/E): E, G♯ and C, with E in the bass.
  • Second inversion (Caug/G♯): G♯, C and E, with G♯ in the bass.

Keys that use C augmented

C augmented (C, E and G♯) is not a diatonic chord of any major or natural minor key. The augmented fifth does appear in the harmonic and melodic minor scales, where C augmented is the chord on the third degree.

Progressions with C augmented

  • Augmented passing chord in C major (I–I+–IV): C – Caug – F

Frequently asked questions

What notes are in the C augmented chord?

C, E and G♯: root, major third and augmented fifth. Its formula is 1-3-♯5.

Why does C augmented sound the same as E augmented?

Because the augmented chord divides the octave into three major thirds: C, E and G♯. When you invert it, the bass note changes but the notes stay the same distance apart, so C augmented uses the same keys and frets as E augmented.

What is the C augmented chord used for?

Mostly as a passing chord, as in I–I+–IV: on the same root, the fifth of the major triad rises a half step, giving C, E and G♯, which pushes toward IV. It is also the III+ of the harmonic minor scale.