Chord · A Major 9th
Amaj9 Chord
Amaj9 is A, C#, E, G# and B — lush, gentle; jazz ballads and neo-soul.
Amaj9 on every instrument
The same 5 notes, 3 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.
What Amaj9 is made of
Amaj9 (A major ninth) is built from the notes A, C#, E, G#, B, with the interval pattern 1, 3, 5, 7, 9.
Stack 1, 3, 5, 7 and 9 on a root of A and you get A, C#, E, G# and B. That interval recipe is what makes the chord a major ninth chord — move the same shape to another root and the character travels with it, which is why Cmaj9 sounds like a transposed Amaj9.
Major 9th: Lush, gentle; jazz ballads and neo-soul.
Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with C♯ rather than its enharmonic equivalent.
Keys that contain Amaj9
All 5 notes sit inside the scale of 4 keys. The roman numeral marks the degree the chord is rooted on.
Other chords on A
Same root, different colour.
The same major ninth shape, moved
The identical interval recipe, built on other roots.
Questions people ask about Amaj9
- What notes are in the Amaj9 chord?
- Amaj9 is made of A, C#, E, G# and B — the 1, 3, 5, 7 and 9 degrees of a major ninth chord built on A.
- What keys use the Amaj9 chord?
- Every note of Amaj9 belongs to 4 keys: A Major (I), E Major (IV), F# Minor (III), C# Minor (VI). The roman numeral is the scale degree the chord is rooted on.
- How do you play Amaj9 on guitar and piano?
- This page shows Amaj9 on guitar, piano and ukulele — 6 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
Learn the theory behind it
Why Amaj9 behaves the way it does — the guides that explain the chord instead of just spelling it.