The augmented seventh chord, or seventh augmented fifth chord,[1] or seventh sharp five chord is a seventh chord composed of a root, major third, augmented fifth, and minor seventh (1, 3, ♯5, ♭7).[2] It can be viewed as an augmented triad with a minor seventh.[3] When using popular-music symbols, it is denoted by +7, aug7,[2] or 7♯5. For example, the augmented seventh chord built on A♭, written as A♭+7, has pitches A♭-C-E-G♭:
| Component intervals from root | |
|---|---|
| minor seventh | |
| augmented fifth | |
| major third | |
| root | |
| Tuning | |
| 80:100:125:144 | |
| Forte no. / | |
| 4-24 / |
The chord can be represented by the integer notation {0, 4, 8, 10}.
Use
The root is the only optional note in an augmented seventh chord, the fifth being required because it is raised.[4] This alteration is useful in the major mode because the raised 5th creates a leading tone to the 3rd of the tonic triad.[3] See also dominant.
In rock parlance, the term augmented seventh chord is sometimes confusingly and erroneously used to refer to the so-called "Hendrix chord", a 7♯9 chord which contains the interval of an augmented ninth but not an augmented fifth.[5]
The augmented minor seventh chord may be considered an altered dominant seventh and may use the whole tone scale, as may the dominant seventh flat five chord.[7] See chord-scale system.
The augmented seventh chord normally resolves to the chord a perfect fifth below.[8] Thus, G aug7 resolves to a C major or minor chord, for example.
Augmented seventh chord table
Chord Root Major third Augmented fifth Minor seventh Caug7 C E G♯ B♭ C♯aug7 C♯ E♯ (F) G 
(A)B D♭aug7 D♭ F A C♭ (B) Daug7 D F♯ A♯ C D♯aug7 D♯ F (G)A (B)C♯ E♭aug7 E♭ G B D♭ Eaug7 E G♯ B♯ (C) D Faug7 F A C♯ E♭ F♯aug7 F♯ A♯ C (D)E G♭aug7 G♭ B♭ D F♭ (E) Gaug7 G B D♯ F G♯aug7 G♯ B♯ (C) D (E)F♯ A♭aug7 A♭ C E G♭ Aaug7 A C♯ E♯ (F) G A♯aug7 A♯ C (D)E (F♯)G♯ B♭aug7 B♭ D F♯ A♭ Baug7 B D♯ F (G)A
