A added ninth
How to play Aadd9 — Added ninth
Aadd9 (Added ninth)A · C♯ · E · B
Guitar samples: Acoustic guitar — University of Iowa (via tonejs-instruments, CC-BY 3.0)
A added ninth — notes and structure
The Aadd9 chord is a major chord with an added ninth for extra colour, without the seventh of a full ninth chord.
The Aadd9 added ninth consists of the notes A, C♯, E, B. Its interval structure is R–3–5–9 — the root, then each chord tone stacked above it. This is the same chord you see in the interactive finder above, drawn on the guitar fretboard with the root circled and every chord tone labelled.
Aadd9 stacks a major third (C♯), a perfect fifth (E) and a ninth (B) above the root A.
The finder shows 2 ways to play Aadd9 — an open-position shape reaching up to the 7th fret. None of them need a barre.
What key is Aadd9 in?
Every note of Aadd9 belongs to the scales below, so the chord sounds at home in each of these keys — the roman numeral is the degree it sits on.
- D major — the V chord
- A major — the I chord
- E major — the IV chord
- B minor — the VII chord
Chords that go with Aadd9
In D major, the chords built on the first, fourth and fifth degrees carry most songs — put Aadd9 next to these:
Frequently asked questions
- What notes are in the A added ninth chord?
- The Aadd9 chord contains the notes A, C♯, E, B. It is a major chord with an added ninth for extra colour, without the seventh of a full ninth chord.
- How many ways can you play Aadd9 on guitar?
- 2 voicings are shown on this page — from open position up the neck — each with its own fingering diagram and audio.
- Is Aadd9 a hard chord to play?
- It is fairly beginner-friendly — there is an open-position shape and none of the voicings need a barre.
- What key does Aadd9 belong to?
- Aadd9 fits D major (where it is the V chord), A major (where it is the I chord), E major (where it is the IV chord) — every note of the chord is in those scales.