A9 Chord
The A9 chord is a dominant ninth chord built on the root note A. Its notes are A, C♯, E, G and B.
Dominant ninth chords are a dominant seventh with extra shine. The ninth on top softens the bite of the tritone below it, which is why funk, soul and blues rhythm guitar lives on this chord.
A9 on piano
To play A9 on piano, take A in the left hand and the remaining notes - C♯, E, G and B - in the right. Press all keys at the same time and listen for a clear, balanced sound. Practice switching to and from this chord slowly, then with a metronome at a comfortable tempo.
A9 on guitar
Open
On guitar, A9 is commonly played with the voicing shown above. If the chord contains barred notes, keep your index finger flat across the fretboard and curve the other fingers so they don't mute the open strings. Strum only the strings marked as active in the diagram for the cleanest tone.
Play the chord
A9 chord notes
| Degree | Interval | Semitones | Note |
|---|---|---|---|
| 1 | Root | 0 | A |
| 3 | Major third | 4 | C♯(C#) |
| 5 | Perfect fifth | 7 | E |
| ♭7 | Minor seventh | 10 | G |
| 9 | Major ninth | 14 | B |
How to use the A9 chord
The A9 chord is built from a root, a major third, a perfect fifth, a minor seventh and a major ninth. Starting from the root A, stack the intervals to get the complete chord: A, C♯, E, G and B. Learning the formula is the fastest way to transpose the chord to any other key.
Dominant ninth chords take the place of a plain dominant seventh in blues, funk, soul and jazz. As the V9 they resolve just like a V7 does, only with more colour on the way.
Common progressions
The A9 chord works beautifully in these progressions. Click a chord name to jump to its page.
Related chords to A9
Once you are comfortable with A9, explore neighbouring chords to unlock new progressions. The chords below share notes, keys or functions with A9 and are a natural next step in your practice.
Frequently asked questions
What notes are in the A9 chord?
Is the A9 chord major or minor?
How do you play A9 on piano?
How do you play A9 on guitar?
What chords work well with A9?
Keep exploring
Deepen your understanding of the A9 chord with our other music theory tools.