C♯aug chord on piano
The C♯aug chord, or C sharp augmented, stacks 3 notes on C♯: C♯, E♯ and G𝄪. Musicians write its formula 1 3 ♯5.
Notes and intervals of C♯aug
Each note of C♯aug 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 C♯aug on piano
Put your right-hand thumb on C♯, then add the other notes: C♯, E♯ and G𝄪. Teachers usually suggest the fingering 1-3-5 (left hand: 5-3-1). Press the keys together, release, and repeat until the chord sounds even.
Inversions of C♯aug
An inversion keeps the same notes but puts another one in the bass. C♯aug has 2 inversions besides root position: 1st inversion (E♯ G𝄪 C♯) and 2nd inversion (G𝄪 C♯ E♯). Inversions let you move between chords with tiny hand movements, which is how pianists make progressions sound smooth.
Which keys use C♯aug?
C♯aug 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 C♯aug
No common scale on C♯ contains every note of C♯aug. 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.
Play 1 3 ♯5 with fingers 1 3 5. The hand shape is identical in every inversion because each gap is a major third. As a passing chord, hold the root and third and move only the fifth up a semitone, then again (5, ♯5, 6). The left hand can sustain the root throughout.
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 C♯aug chord?
C♯aug (C sharp augmented) contains C♯, E♯ and G𝄪. In intervals: root (C♯), major 3rd (E♯) and augmented 5th (G𝄪).
How do you play C♯aug on piano?
Play C♯, E♯ and G𝄪 together with the right-hand fingering 1-3-5. You can also play it in 2 inversions, shown on this page.
What scale goes with C♯aug?
No common scale on C♯ contains every note of C♯aug; improvise with its arpeggio, C♯, E♯ and G𝄪.
What key is C♯aug in?
C♯aug 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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