A♯dim7 chord
A♯dim7 is A♯, C♯, E and G: 1–♭3–♭5–♭♭7 built on A♯. Below: guitar, piano and ukulele, each playable.
On guitar
x-1-2-0-2-0 · open · easy
- Notes
- A♯ · C♯ · E · G
- Formula
- 1 · ♭3 · ♭5 · ♭♭7
- First shape
- x-1-2-0-2-0
A♯dim7 on guitar: every shape, finger by finger
On piano
root position · A♯–C♯–E–G · right hand 1-2-3-5
- Notes
- A♯ · C♯ · E · G
- Formula
- 1 · ♭3 · ♭5 · ♭♭7
A♯dim7 on piano: fingering and inversions
On ukulele
0-1-0-1 · open · easy
- Notes
- A♯ · C♯ · E · G
- Formula
- 1 · ♭3 · ♭5 · ♭♭7
- First shape
- 0-1-0-1
Changing out of A♯dim7
Three changes cover most of what A♯dim7 does in songs.
- A♯dim7 → B (leads up a half step)
Guitar: A♯dim7 (x-1-2-0-2-0) to B (x-2-4-4-4-2): the index finger lays across the A to high E strings at the 2nd fret, your middle finger lands on the D string, 4th fret, the ring finger goes to the G string, 4th fret, the pinky finger comes down on the B string, 4th fret. Nothing carries over, so drill it slowly, lifting and landing all fingers at once.
Piano: A♯dim7 to B: play B in root position (B–D♯–F♯), while A♯ moves up to B, E down to D♯ and G down to F♯. B - A♯dim7 → Bm (leads up a half step)
Guitar: A♯dim7 (x-1-2-0-2-0) to Bm (x-2-4-4-3-2): the index finger lays across the A to high E strings at the 2nd fret, your middle finger lands on the B string, 3rd fret, the ring finger goes to the D string, 4th fret, the pinky finger comes down on the G string, 4th fret. No finger can stay, so practice lifting all of them together and landing the new shape as a unit.
Piano: A♯dim7 to Bm: play Bm in root position (B–D–F♯), while A♯ moves up to B, C♯ up to D and G down to F♯. Bm - A♯dim7 → E♭ (a fifth down)
Guitar: A♯dim7 (x-1-2-0-2-0) to E♭ (x-x-1-3-4-3): the index finger slides across to the D string at the same fret, move the middle finger to the G string, 3rd fret, the ring finger goes to the high E string, 3rd fret, the pinky finger comes down on the B string, 4th fret. No finger can stay, so practice lifting all of them together and landing the new shape as a unit. A♯ and G carry over from one chord to the other.
Piano: A♯dim7 to E♭: play E♭ in 2nd inversion (B♭–E♭–G) and B♭ and G stay under the same fingers, while E moves down to E♭. E♭
How A♯dim7 is built
A♯dim7 is a diminished seventh: three minor thirds stacked, so the chord divides the octave into four equal parts. That symmetry means A♯dim7 contains exactly the same four notes as C♯dim7, Edim7 and Gdim7; which name you use depends on the bass note and the key.
Count keys (black and white) from A♯: 3 half steps up to C♯, 3 half steps up to E then 3 half steps up to G. B♭dim7 is the other spelling of the same chord.
| Note | Role | Half steps | Hear it |
|---|---|---|---|
| A♯ | root | 0 | |
| C♯ | minor third | 3 | |
| E | diminished fifth | 6 | |
| G | diminished seventh | 9 |
Keys and progressions with A♯dim7
No major or natural minor key contains A♯dim7 as one of its own chords; it turns up as a passing chord on the way somewhere else.
Chords close to A♯dim7
- A♯dim7 is B♭dim plus G. B♭dim
Chords that share most of their notes with A♯dim7: C♯dim7, Edim7, Gdim7, C♯dim, Edim, Gdim.
Every A♯ chord
A♯dim7 chord: questions
What notes are in the A♯dim7 chord?
A♯, C♯, E and G. A♯dim7 is built 1–♭3–♭5–♭♭7 from A♯: C♯ is the minor third, E is the diminished fifth and G is the diminished seventh.
How do you play A♯dim7 on guitar?
The usual shape is x-1-2-0-2-0 (open). All 4 guitar shapes.
How do you play A♯dim7 on piano?
Play A♯, C♯, E and G with right-hand fingers 1-2-3-5. A♯ sits on the last black key of the group of three. Inversions and left hand.
How do you play A♯dim7 on ukulele?
0-1-0-1 in standard GCEA tuning. More ukulele shapes.
What key is A♯dim7 in?
No major or natural minor key contains A♯dim7 as one of its own chords; it turns up as a passing chord on the way somewhere else.
What's the difference between A♯dim7 and B♭dim?
A♯dim7 is B♭dim plus G.
All three instruments are drawn and played from A♯, C♯, E and G by the same engine. Updated September 2026.