Caug chord on guitar
The Caug chord, or C augmented, stacks 3 notes on C: C, E and G♯. Musicians write its formula 1 3 ♯5.
Notes and intervals of Caug
Each note of Caug has a job. Counted from the root, you get root (C), major 3rd (E) and augmented 5th (G♯). Change one of these intervals and you get a different chord, which is why the formula 1 3 ♯5 is worth memorising rather than the shape alone.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | C |
| 3 | major 3rd | E |
| ♯5 | augmented 5th | G♯ |
How to play Caug on guitar
Start with the first diagram: x 3 2 1 1 x, read from the 6th string (low E) to the 1st string (high E). Your lowest note is C. The next positions give the same notes in a different order, which is useful when you want Caug to sit closer to the surrounding chords.
This is a barre or movable shape: keep your index finger straight and close to the fret, and press with the side of the finger rather than the flat pad.
Which keys use Caug?
Caug is not built from the notes of a single major key, so it usually appears as a colour chord: a borrowed chord, a passing chord or a suspension that resolves to the next chord.
Scales to play over Caug
No common scale on C contains every note of Caug. Improvise with the arpeggio (play only C, E and G♯) and add passing notes between them.
About augmented chords
Two stacked major thirds: 1 3 ♯5. The raised fifth makes it strange, dreamy and suspended in mid-air. The augmented chord is symmetrical: it splits the octave into three equal major thirds, so three augmented chords a major third apart share the same notes (for example Caug, Eaug and G♯aug). For example Caug: C E G♯.
Its most common role is a passing chord: I I+ IV or I I+ vi, where the fifth climbs chromatically (for example C, C+, F: G, G♯, A). It also works as an altered dominant, V+ to I, where the ♯5 leads up to the third of the next chord. Jazz standards, 1960s pop and film music use it for that rising tension.
Most guitarists use a compact four-string shape on the middle or top strings. Because the chord is symmetrical, the same shape moved up 4 frets gives the same notes with another note in the bass, so one shape covers three chords. Open shapes exist (for example Caug x32110), but the movable shape is more useful.
aug is not 7♯5: 7♯5 adds a minor seventh. The symbols +, aug and (♯5) all mean the same triad. And spelling matters: the top note is a raised fifth (G♯ in Caug), not a minor sixth (A♭), even if they sound the same: G♯ moves up, while A♭ would move down.
Frequently asked questions
What notes are in the Caug chord?
Caug (C augmented) contains C, E and G♯. In intervals: root (C), major 3rd (E) and augmented 5th (G♯).
How do you play Caug on guitar?
The easiest shape is x 3 2 1 1 x, from the low E string to the high E string. This page shows 3 positions with finger numbers.
What scale goes with Caug?
No common scale on C contains every note of Caug; improvise with its arpeggio, C, E and G♯.
What key is Caug in?
Caug does not belong to a single major key. It is used as a colour chord that borrows notes from outside the key.
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