A9 Piano Chord

A9 is the A dominant ninth chord. It has five notes: A, C sharp, E, G and B. The stack is wider than an octave, so most players take A with the left hand and the other four notes with the right.

A at the bottom, then C♯, E, G and B. Right hand 1-2-3-4-5 if the span is there; otherwise A in the left hand and the rest in the right.

How to play A9 on piano, step by step

Start on the A below middle C. That is the lowest note of the chord.
Thumb (1): A
Index finger (2): C♯
Middle finger (3): E
Ring finger (4): G
Little finger (5): B
That reach is wider than an octave, so most players split it: play A with the left hand and the other notes with the right. If you keep it in one hand, use the two-hand split shown on this page. Leaving out the fifth (E) can thin the sound, but it does not shorten the span from the root to the ninth.

A7 is this chord without the top note. Play A, C sharp, E and G first, then add B with the little finger and listen to the chord fill out.

If it sounds wrong

The reach is too wide: A to B is a ninth. Put A in the left hand and C sharp, E, G and B in the right; that split is the normal way to play this chord, not a workaround.
It sounds dreamy instead of bluesy: Check the G is natural. G sharp turns the chord into Amaj9, the soft cousin. A9 needs the plain white key G.
The C sharp gets lost: The third is the only black key in the shape and it sits low, under the index finger. Let the hand settle far enough into the keys that the index lands squarely on it.

What makes it an A9

A · C♯ · E · G · B 1 3 5 ♭7 9

A9 is an A7 chord with a B added: A, C sharp, E and G make the seventh, and the B a ninth above the root rounds it into A9.

A9 is the V9 of D, the seventh chord blues, soul and funk actually play instead of the plain A7. A blues in A leans on this chord from the first bar, and in the key of D it is the V that leads home.

A9 vs A7

A9 is A7 with a B on top. Both pull toward D; the ninth is the smoother, more finished sound.

Play A7 and add B with the little finger. Nothing about the chord's job changes, only the colour. In blues and funk, where the seventh chord is home, the ninth is what players actually voice.

A9 in major keys

Every note of A9 sits inside these keys. See how it works alongside the other chords in each one.

D major (V)

Questions about A9

Which notes are in an A9 chord on piano?

A, C sharp, E, G and B. C sharp is the only black key, and the B on top is the ninth.

What is the difference between A9 and Aadd9?

The seventh. A9 contains G; Aadd9 is the plain A major chord with a B added and no seventh, so it sits at rest where A9 pushes forward.

Why does this page show no inversions?

This page teaches one practical root-position voicing because a ninth spans more than an octave. Ninth chords can still be inverted: an inversion changes the bass note, and players often reorder or omit notes to fit the hand. The diagrams here keep the beginner-friendly voicing visible.

Can I leave a note out of A9?

The fifth (E) can be omitted when another part supplies the root; this thins the voicing without changing the chord quality.

Where is the A9 chord used?

As the V chord of D and all through a blues in A. Soul, funk and gospel use it wherever A7 would appear.