Chords
Augmented chord
An augmented chord is a triad made of two stacked major thirds: a root, a major third and an augmented fifth, such as C E G♯ for C+.
What is an augmented chord?
An augmented chord is the triad with the formula 1 3 ♯5: two major thirds stacked (4 + 4 semitones). Compared with a major chord, only the fifth changes: it is raised by a semitone. C = C E G, C+ = C E G♯.
Symbols: "aug", "+" or "(♯5)". C+, Caug and C(♯5) all mean the same chord. It sounds floating and unresolved, like a question waiting for its answer.
Why is the augmented chord symmetrical?
Three major thirds add up to exactly one octave (4 + 4 + 4 = 12 semitones). So the augmented chord splits the octave into three equal parts, and every inversion has the same interval stack. As a result, C+, E+ and G♯+ contain the same notes (C, E, G♯, with B♯ = C and D♯♯ = E in strict spelling).
That means there are only four different augmented chords: C+, C♯+, D+ and D♯+. All their notes belong to the whole-tone scale, the chord's natural home scale.
How do you play an augmented chord on guitar?
Two open shapes, from low E to high E:
- C+ =
x32110(C E G♯ C E): the open C chord with the 3rd-string finger on the 1st fret. - G+ =
321003(G B D♯ G B G): the open G chord with the 4th string on the 1st fret.
On strings 3, 2, 1, C+ sits at frets 5, 5, 4. Thanks to the symmetry, the same shape moved up 4 frets (9, 9, 8) and 8 frets (13, 13, 12) is still C+. The chord identifier makes this obvious: enter C, E and G♯ and it offers all three possible names.
Exercises: two classic uses
1. Augmented V to I. Play G 320003, G+ 321003, then C x32010. The D♯ in G+ rises a semitone to the E of C, a resolution that feels inevitable.
2. The chromatic line. Keep the C shape and move just one finger on the 3rd string:
- C
x32010(G) - C+
x32110(G♯) - C6
x32210(A) - C7
x32310(B♭) - F
xx3211
The inner voice climbs G, G♯, A, B♭ while the bass stays on C. You'll hear this move in countless pop ballads and jazz standards.
Common mistakes with augmented chords
- Confusing augmented with diminished: augmented raises the fifth (1 3 ♯5), diminished lowers the third and the fifth (1 ♭3 ♭5).
- Reading "+" as "add": C+ adds nothing, it replaces G with G♯.
- Looking for it in the major scale: it isn't there. It appears on the III degree of harmonic minor (C+ in A harmonic minor) or as a chromatic alteration.
Key takeaways
- Formula: 1 3 ♯5, two major thirds.
- Symmetrical: C+ = E+ = G♯+, so the shape repeats every 4 frets.
- Core shapes: C+
x32110, G+321003, frets 5-5-4 on the top strings. - Uses: V+ to I, and the chromatic line C, C+, C6, C7.
Frequently asked questions
What is an augmented chord used for?
Mostly to create motion: the raised fifth pulls toward the note a semitone above. G+ goes to C, C+ goes to F (G♯ rises to A). It also works as a dreamy colour in intros and ballads.
What is the difference between C+ and Caug?
None: they are two ways of writing the same chord, C E G♯. You'll also see C(♯5), and in jazz C7♯5 or C7+ when a minor seventh is added (C E G♯ B♭).
What scale fits an augmented chord?
The whole-tone scale is the most natural choice: over C+, play C D E F♯ G♯ A♯. It contains all three chord tones and keeps the floating sound.
Related terms
Practise in the workshop
Take it from theory to the fretboard
Open the workshop tools and see this idea across the whole neck. Free account, no card needed.