Augmented seventh chord
The augmented seventh chord: a dominant seventh with a raised fifth. The raised fifth adds tension, and jazz often uses it as an altered dominant. Spelled in all twelve keys, with guitar shapes and piano diagrams.
On C
- Symbol
- C7♯5
- Formula
- 1 3 ♯5 ♭7
- Notes
- 4
- Also written
- C+7 · C7♯5 · Caug7
What it sounds like
C7♯5 is C, E, G♯ and B♭: a dominant seventh with the fifth raised. The raised fifth removes the stability of the perfect fifth and leaves the chord with an open, sharp sound. The chord contains the augmented triad C, E, G♯. The minor seventh and the tritone between E and B♭ still drive the chord forward. Its sound is unstable and strongly directional, and it is most often heard as a dominant heading to a tonic a fourth above.
How it is used
The augmented seventh is a dominant chord and moves like one, with its root falling a fifth to the tonic. In jazz it is an altered dominant, used on the V of ii, V, I progressions, and it often takes the place of a plain dominant seventh. Classical music uses the raised fifth in chromatic passages. Popular music uses it more sparingly, mostly in jazz-influenced writing. In those contexts the raised fifth gives the chord its altered sound.
How it is built
The augmented seventh is a root with a major third, an augmented fifth and a minor seventh, 0, 4, 8 and 10 semitones above the root. Common symbols are C7♯5, C7+5, C7aug, C+7 and C7(♯5). The raised fifth, G♯, is the same pitch as A♭, so the chord can be spelled C, E, A♭ and B♭, though writers rarely do. Its inversions put E, G♯ or B♭ in the bass.
How to practise it
Play C7, then C7♯5, then C7 again, changing only the G to G♯ and back. Listen to the one-semitone change that turns a plain dominant into an altered one. Then play the same chord with the G♯ on top, as a passing chord before F major. Keep the hand position fixed so that the single moving note is the only change.
Augmented seventh chord in every key
Every chord is spelled by letter name. Click a symbol for its page, with inversions and guitar shapes.
| Chord | Notes | Hear it |
|---|---|---|
| C7♯5 | C E G♯ B♭ | |
| D♭7♯5 | D♭ F A C♭ | |
| D7♯5 | D F♯ A♯ C | |
| E♭7♯5 | E♭ G B D♭ | |
| E7♯5 | E G♯ B♯ D | |
| F7♯5 | F A C♯ E♭ | |
| G♭7♯5 | G♭ B♭ D F♭ | |
| G7♯5 | G B D♯ F | |
| A♭7♯5 | A♭ C E G♭ | |
| A7♯5 | A C♯ E♯ G | |
| B♭7♯5 | B♭ D F♯ A♭ |
Further reading
- Seventh Chords and How They Resolve in Tonal HarmonyHarmony · 7 min
- Chord Symbols Explained: Major, Minor, Seventh and Slash ChordsHarmony · 8 min
- Chord Extensions Explained: Ninths, Elevenths and ThirteenthsJazz & Popular Harmony · 7 min
Questions
What is the difference between C7 and C7♯5?
C7 is C, E, G and B♭. C7♯5 raises the fifth to G♯, so the chord is C, E, G♯ and B♭. The raised fifth removes the perfect fifth and adds a sharper, more altered sound. Both chords keep the major third and the minor seventh, so both act as dominants.
What does C7+5 mean?
C7+5 and C7♯5 are two symbols for the same chord: C, E, G♯ and B♭. The plus sign is common in jazz and pop charts, and the sharp sign is common in printed harmony texts. Writers also use C7aug and C+7 with the same meaning. Read the notes, not the symbol, to know which pitches to play.
Is the augmented seventh a dominant chord?
Yes. It has a major third and a minor seventh, so it keeps the dominant structure and the tritone between E and B♭ that drives the chord toward a tonic. The raised fifth changes the sound but keeps the function, so the chord still moves to a tonic in most contexts.