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A9 chord

A9 (A dominant ninth) is A, C♯, E, G and B. It sounds full and funky, a seventh chord with more colour.

A9

A dominant ninth · A C♯ E G B · 1 3 5 ♭7 9

AEGBC♯

Or pick another chord to see and hear it

Root
Chord

Tap keys on the piano to find which chord they make. The editor opens without an account.

Notes in the A9 chord

From A, count 4 half steps up to C♯, 3 more to E, 3 more to G and 4 more to B. Its formula is 1 3 5 ♭7 9: each number is the note’s place in the A major scale, with ♭ a half step lower and ♯ a half step higher. On the piano it is four white keys and one black key (C♯).

The notes of A9 and their intervals from A
NoteFormulaIntervalHalf steps up
A1Root0
C♯3Major third4
E5Perfect fifth7
G♭7Minor seventh10
B9Major ninth14

A9 chord inversions

An inversion is the same chord with another of its notes at the bottom. It keeps the chord’s sound but moves your hand less between chords, which is why pianists use them all the time. The notes are listed lowest first.

Root position

A C♯ E G B

Written A9, with the root at the bottom.

1st inversion

C♯ E G B A

Written A9/C♯: C♯ at the bottom.

2nd inversion

E G B A C♯

Written A9/E: E at the bottom.

3rd inversion

G B A C♯ E

Written A9/G: G at the bottom.

4th inversion

B A C♯ E G

Written A9/B: B at the bottom.

Keys with the A9 chord

A9 is built from the notes of these keys, so it fits songs in them. The Roman numeral says which note of the key it starts on. Each key’s page has its scale and all its chords.

Major keys
Minor keys

Chords that often come after A9

DD F♯ AA9 is the V9 of D: it resolves there like a V7, with more colour.DmD F AThe same pull into Dm, home in the minor key.

More piano chords

Other chords on A

AAmA7Amaj7Am7Asus2Asus4Aadd9A6AdimAm7♭5Adim7Aaug

Dominant ninth chords on other notes

C9C♯9D9E♭9E9F9F♯9G9A♭9B♭9B9

Or see every chord at once on the piano chords chart.

Frequently asked questions

What notes are in the A9 chord?

A9 is A, C♯, E, G and B. On the piano that is four white keys and one black key (C♯).

How do you play A9 on the piano?

Most pianists play the root, A, with the left hand and the other four, C♯, E, G and B, with the right hand (fingers 1, 2, 3 and 5). From A, count 4 half steps up to C♯, 3 more to E, 3 more to G and 4 more to B.

What are the inversions of A9?

Root position: A C♯ E G B. 1st inversion: C♯ E G B A (A9/C♯). 2nd inversion: E G B A C♯ (A9/E). 3rd inversion: G B A C♯ E (A9/G). 4th inversion: B A C♯ E G (A9/B). The notes are the same; only the lowest one changes.

What key is A9 in?

In major keys, A9 is the V9 chord in D major. In minor keys, it is the VII9 chord in B minor.

Can I make a beat with A9?

Yes. “Make a beat in D major” opens the free editor with a lo-fi beat in D major on D A Bm G, the key where A9 is the V9 chord. Then change any part, add a melody and your voice, part by part. No account is needed to start.

Make a beat in D major

Opens the free editor with a lo-fi beat in D major on D A Bm G, the key where A9 is the V9 chord. Then change any part, add a melody and your voice, part by part. No account needed to start.

Make a beat in D majorAll piano chords

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