Aadd9 — A, C♯, E, B — is an add9 chord: major triad + 9th (no 7th in between) — a brighter alternative to a plain major chord, popular in pop, indie, and modern songwriting.
Intervals
The A add 9 chord stacks two thirds on the root. Each interval and its size in semitones:
- A→C#major 3rd4 semitones
- C#→Eminor 3rd3 semitones
- E→Bperfect 5th7 semitones
On the keyboard
Each note of the A add 9 chord highlighted on a piano. Pitch class is what matters — any octave works.
On the guitar
One voicing of the A add 9 chord on a six-string guitar fretboard.
- 1A
- 3C#
- 5E
- 9B
Common mistakes
The defining note is the 9th (B). It sits more than an octave above the root, which is why the chord needs a wide voicing — in tight piano voicings the 9th usually appears in the top register while the root and lower triad tones cluster below.
In context
Functions as a bright tonic alternative in major-key pop, country, and modern songwriting.
Drill it
The A add 9 chord is one of 48 in the Chord Trainer. Open the full trainer to practice it alongside related chords with timing and best-time tracking.
Open the Chord Trainer →Or try today's Etudle puzzleRelated
Frequently asked
- What notes are in a Aadd9 chord?
- Aadd9 contains four notes: A, C♯, E, B.
- How is Aadd9 different from Amaj7?
- Aadd9 adds the 9th (B) on top of the underlying 7th chord. The 9th extends the chord into the next octave and adds harmonic colour.
- When is Aadd9 used in music?
- Functions as a bright tonic alternative in major-key pop, country, and modern songwriting.