A9 chord on piano
A9 is A, C♯, E, G and B. A is the white key between the last two black keys of the three. Hit Play and watch each key light as it sounds.
root position · A–C♯–E–G–B · right hand 1-2-3-4-5
- Notes
- A · C♯ · E · G · B
- Formula
- 1 · 3 · 5 · ♭7 · 9
How to play A9 on piano
Start on A, count 4 half steps up to C♯, 3 half steps up to E, 3 half steps up to G then 4 half steps up to B. That's the whole chord: 5 keys.
- Right hand: 1 on A, 2 on C♯, 3 on E, 4 on G and 5 on B.
- Left hand: 5 on A, 4 on C♯, 3 on E, 2 on G and 1 on B.
- On the keyboard it's white, black, white, white and white keys, the same pattern as D9, so your hand shape carries over.
Two ways to voice A9
- root position: A–C♯–E–G–B. RH 1-2-3-4-5.
- close voicing: A–B–C♯–E–G. RH 1-2-3-4-5.
The close voicing folds the ninth down next to the root, which fits under one hand; the spread voicing sounds wider.
Changing from A9 to the chords around it
These are the changes you'll meet most often with A9, using the first shape of each chord.
- D (dominant, pulls to the chord a fifth below): A9 to D: play D in 2nd inversion (A–D–F♯) and A stays under the same finger, while C♯ moves up to D and G down to F♯. D on piano
- Dmaj7 (I in D major): A9 to Dmaj7: play Dmaj7 in 2nd inversion (A–C♯–D–F♯) and A and C♯ stay under the same fingers, while E moves down to D and G down to F♯. Dmaj7 on piano
- Bm7 (vi in D major): A9 to Bm7: play Bm7 in 1st inversion (D–F♯–A–B) and B stays under the same finger, while C♯ moves up to D, G down to F♯ and G up to A. Bm7 on piano
A9 is a dominant ninth: A7 with the ninth on top. A9 is the funk and soul version of A7, fuller on top and still pulling toward its resolution. Play it solid and then broken to hear the difference.
Getting A9 under your fingers
Start with a broken chord, A C♯ E G B G E C♯ A, then play it solid.
The keys of A9
A9 is a dominant ninth chord, 1–3–5–♭7–9 from A. Root position, from the bottom: how A9 is built.
| Note | Key | Fingers | Role |
|---|---|---|---|
| A | white key | RH 1 · LH 5 | root |
| C♯ | black key | RH 2 · LH 4 | major third |
| E | white key | RH 3 · LH 3 | perfect fifth |
| G | white key | RH 4 · LH 2 | minor seventh |
| B | white key | RH 5 · LH 1 | ninth |
A9 in context
A9 on guitar and ukulele
A9 on guitar and ukulele uses the same 5 notes in a different layout. See all three together.
Close to A9
Other dominant ninth chords
A9 on piano: questions
What notes are in A9 on piano?
A, C♯, E, G and B: A (white key), C♯ (black key), E (white key), G (white key) and B (white key). Right hand 1-2-3-4-5, left hand 5-4-3-2-1.
How do you play A9 on piano?
Press A, C♯, E, G and B together (1 black, 4 white). Right hand: 1 on A, 2 on C♯, 3 on E, 4 on G and 5 on B.
What are the inversions of A9?
A9 is usually played in root position (A–C♯–E–G–B) or as a close voicing (A–B–C♯–E–G).
What does A9 look like on the keyboard?
white, black, white, white and white keys, the same pattern as D9, so one hand shape covers all of them.
Checked automatically: no shape here plays a note outside A9. Updated September 2026.