A9 (dominant ninth)
5-note dominant 9th on A — A, B, C♯, E, G.
Press to hear the chord strummed low to high.
A dominant seventh extended with the ninth — funky and full, the sound of a James Brown horn stab.
The notes
Pitches taken from the first fingering below — click any note to open its frequency page.
Interval formula
| Degree | Note | What it is |
|---|---|---|
| 1 | A | root |
| 9 | B | ninth |
| 3 | C♯ | major third |
| 5 | E | perfect fifth |
| ♭7 | G | flat seventh (dominant) |
The formula reads in semitones above the root (A): 1, 9, 3, 5, ♭7. A voicing may leave a tone out — often the fifth — but never adds one from outside this set.
Guitar fingerings · 4
Ukulele fingerings · 4
Read a diagram top-down: the thick bar is the nut, dots are where to press (the number is which finger), means play the open string, means don't play it. A bar across strings is a barre.
Other A chords
- major
- 6 (major sixth)
- 6/9
- maj7 (major seventh)
- maj9 (major ninth)
- maj11 (major eleventh)
- maj13 (major thirteenth)
- add9
- add11
- maj7♭5
- maj7♯5 (augmented major 7th)
- minor
- m6 (minor sixth)
- m6/9
- m7 (minor seventh)
- m7♭5 (half-diminished)
- m(maj7) (minor-major seventh)
- m9 (minor ninth)
- m11 (minor eleventh)
- m(add9)
- m(maj7)♭5
- m(maj9)
- m(maj11)
- m9♭5
- 7 (dominant seventh)
- 7♭5
- 7♭9
- 7♯9 (the "Hendrix chord")
- 7♯5 (augmented seventh)
- alt (altered dominant)
- 9♭5
- 9♯5 (augmented ninth)
- 9♯11
- 11 (dominant eleventh)
- 13 (dominant thirteenth)
- 7♭9♯5
- 13♭9
- 13♭5♭9
- 7♭13♭9
- 7♭13♯9
- sus2 (suspended 2nd)
- sus4 (suspended 4th)
- sus (suspended 4th)
- sus2sus4
- 7sus4
- maj7sus2
- 5 (power chord)
- dim (diminished)
- dim7 (diminished seventh)
- aug (augmented)