3 notes · 1 · 3 · ♯5

C Augmented Piano Chord (Caug)

Caug is built from C, E and G# — the formula 1 · 3 · ♯5, or 4 and 8 semitones above C. The shape uses 2 white and 1 black key, and you can hear it, invert it and compare it below.

Root noteChord type

Chord

C Augmented

Notes

C · E · G#

Formula

1 · 3 · ♯5

Right hand

1 · 3 · 5

Choose a chord, then play it. Finger numbers run from thumb (1) to little finger (5).

The finder above already holds Caug. Press P or the Play chord button to hear C, E, G# sounded together, then change the root or the chord type to compare it with something else.

Chord tones

The notes in Caug

An augmented triad is two major thirds stacked, so the fifth is raised by a semitone. Every note sits four semitones from the next, which leaves the chord without an obvious home and gives it a suspended, slightly uneasy colour. It is not diatonic to the major scale; it appears on the third degree of the harmonic minor scale and as an altered dominant.

Each tone of C augmented with its interval, scale degree, distance in semitones from C and a suggested right-hand finger.
Note	Interval	Degree	Semitones	Right hand
Cwhite key	Root	1	0	1 · thumb
Ewhite key	Major third	3	4	3 · middle finger
G#black key	Augmented fifth	♯5	8	5 · little finger

Step by step

How to play Caug on piano

Find C: it is the white key immediately left of every group of two black keys.
Build upwards from C using 4 and 8 semitones to reach E and G#.
With the right hand, place finger 1 on C, finger 3 on E and finger 5 on G#. Keep the wrist level and the knuckles rounded.
Move your hand a little further in towards the fallboard so the black key sits comfortably under your fingers.
Play the notes together, then one at a time from the bottom up, and listen to how Caug settles.
Try first inversion as well: E – G# – C. Inversions let you change chords without jumping around the keyboard.

Inversions

Caug in 3 positions

An inversion keeps the same 3 notes and simply moves the lowest one up an octave. Learning them means you can change chords with small hand movements instead of jumping to a new part of the keyboard.

Root position

C – E – G#

The root C is the lowest note. This is the shape most people learn first.

First inversion

E – G# – C

E is the lowest note, so the major third sits in the bass and the notes below it move up an octave.

Second inversion

G# – C – E

G# is the lowest note, so the augmented fifth sits in the bass and the notes below it move up an octave.

In context

Which keys contain Caug

In A harmonic minor the chord functions as III+. It is the only key listed here that produces this chord from its own scale, which is part of why the chord sounds unusual.

A harmonic minorIII+

Chord tones are spelled by the degree they occupy, so the third of a minor chord is written as a flat rather than a sharp even though it is the same key on the piano. A double sharp such as F## means the key one whole tone above F.

Compare

Caug against C major

Caug and C major share C and E. Moving the perfect fifth G up 1 semitone to the augmented fifth G# turns C major into Caug.

Practise the pair together: hold the shared notes C, E still and move only the one finger. Hearing that single change is the quickest way to recognise the two chords by ear.

Open C major →

Good questions

Caug questions

What notes are in the Caug chord?

Caug contains C, E and G#. Counted from the root, that is the formula 1 · 3 · ♯5, or 4 and 8 semitones above C.

What is the right-hand fingering for Caug?

A comfortable beginner fingering is 1 (thumb) on C, 3 (middle finger) on E and 5 (little finger) on G#. Finger numbers run from the thumb (1) to the little finger (5), and they change once you start using inversions.

How is Caug different from C major?

Caug and C major share C and E. Moving the perfect fifth G up 1 semitone to the augmented fifth G# turns C major into Caug.

Which keys use the Caug chord?

It occurs naturally in A harmonic minor (III+). The roman numeral shows which degree of the key the chord is built on.

What are the inversions of Caug?

root position is C – E – G#, first inversion is E – G# – C and second inversion is G# – C – E. Every inversion holds the same notes; only the lowest one changes.