A9 chord (A dominant ninth) on piano
A9 (A dominant ninth) has five notes: A, C sharp, E, G and B. Its formula is 1, 3, 5, b7, 9. In major keys, A9 is the V9 chord in D major.
A9 inversions and fingering
A C# G · LH 5-3-1
A G C# E B · RH 1-2-5 · LH 5-1
Hear it and see every shape in ScaleSpace →
| Symbol | A9 |
|---|---|
| Also written | Adom9 |
| Notes | A C# E G B |
| Formula | 1 3 5 b7 9 |
| Intervals | root, major third, perfect fifth, minor seventh, major second |
| Type | Dominant ninth chord |
A9 across the keyboard
Piano, C3 to C5. Notes in this scale, low to high: C#3 (3), E3 (5), G3 (flat 7), A3 (1), B3 (9), C#4 (3), E4 (5), G4 (flat 7), A4 (1), B4 (9).
Swipe the chart sideways to see all of it.
Questions
What notes are in the A9 chord?
A9 (A dominant ninth) has five notes: A, C sharp, E, G and B. Its formula is 1, 3, 5, b7, 9. A is the root, C# is the major third, E is the perfect fifth, G is the minor seventh and B is the major second.
How do you play A9 on piano?
Play A, C#, E, G and B together. Shell (left hand): A C# G · LH 5-3-1.
What key is A9 in?
In major keys, A9 is the V9 chord in D major. It is diatonic to those keys, so it fits songs in any of them.
What is the difference between A9 and A7?
A9 is A7 (A, C#, E and G) with B, the 9th, added.