B♭ diminished chord (B♭dim)
B♭dim is B♭, D♭ and F♭: 1–♭3–♭5 built on B♭. Here it is on guitar, piano and ukulele. Tap Play on any of them.
On guitar
x-1-2-3-2-x · movable · medium
- Notes
- B♭ · D♭ · F♭
- Formula
- 1 · ♭3 · ♭5
- First shape
- x-1-2-3-2-x
B♭dim on guitar: every shape, finger by finger
On piano
root position · B♭–D♭–F♭ · right hand 1-3-5
- Notes
- B♭ · D♭ · F♭
- Formula
- 1 · ♭3 · ♭5
B♭dim on piano: fingering and inversions
On ukulele
3-1-0-1 · open · easy
- Notes
- B♭ · D♭ · F♭
- Formula
- 1 · ♭3 · ♭5
- First shape
- 3-1-0-1
B♭dim and the chords around it
Here's what the hand does on the most common changes, on guitar and on piano.
- B♭dim → B (leads up a half step)
Guitar: B♭dim (x-1-2-3-2-x) to B (x-2-4-4-4-2): the index finger lays across the A to high E strings at the 2nd fret, move the middle finger to the D string, 4th fret, the ring finger goes to the G string, 4th fret. Nothing carries over, so drill it slowly, lifting and landing all fingers at once.
Piano: B♭dim to B: play B in root position (B–D♯–F♯), while B♭ moves up to B, D♭ up to D♯ and F♭ up to F♯. B - B♭dim → Bm (leads up a half step)
Guitar: B♭dim (x-1-2-3-2-x) to Bm (x-2-4-4-3-2): the index finger lays across the A to high E strings at the 2nd fret, move the middle finger to the B string, 3rd fret, the ring finger goes to the D string, 4th fret. Nothing carries over, so drill it slowly, lifting and landing all fingers at once.
Piano: B♭dim to Bm: play Bm in root position (B–D–F♯), while B♭ moves up to B, D♭ up to D and F♭ up to F♯. Bm - B♭dim → E♭m (iii in B major)
Guitar: B♭dim (x-1-2-3-2-x) to E♭m (x-x-1-3-4-2): the index finger slides across to the D string at the same fret, the middle finger goes to the high E string, 2nd fret, move the ring finger to the G string, 3rd fret. No finger can stay, so practice lifting all of them together and landing the new shape as a unit. The two chords share B♭, which is why the change sounds smooth.
Piano: B♭dim to E♭m: play E♭m in 2nd inversion (B♭–E♭–G♭) and B♭ stays under the same finger, while D♭ moves up to E♭ and F♭ up to G♭. E♭m
How B♭dim is built
B♭dim is a diminished triad: two minor thirds stacked. It sounds tense and unstable and rarely stays long. Its most common job is to lead up a half step, so B♭dim usually moves to B or Bm.
Count keys (black and white) from B♭: 3 half steps up to D♭ then 3 half steps up to F♭. A♯dim is the other spelling of the same chord.
| Note | Role | Half steps | Hear it |
|---|---|---|---|
| B♭ | root | 0 | |
| D♭ | minor third | 3 | |
| F♭ | diminished fifth | 6 |
Keys and progressions with B♭dim
In major keys, B♭dim is vii° in B major. In minor keys it is ii° in G♯ minor.
Chords close to B♭dim
- B♭dim and B♭m differ by one note: F♭ in B♭dim, F in B♭m. They share B♭ and D♭. B♭m
Chords that share most of their notes with B♭dim: C♯m6, C♯dim7, Edim7, F♯7, Gdim7, A♯dim7.
Every B♭ chord
B♭ diminished chord: questions
What notes are in the B♭ diminished chord?
B♭, D♭ and F♭. B♭dim is built 1–♭3–♭5 from B♭: D♭ is the minor third and F♭ is the diminished fifth.
How do you play B♭dim on guitar?
The usual shape is x-1-2-3-2-x (movable). All 4 guitar shapes.
How do you play B♭dim on piano?
Play B♭, D♭ and F♭ with right-hand fingers 1-3-5. B♭ sits on the last black key of the group of three. Inversions and left hand.
How do you play B♭dim on ukulele?
3-1-0-1 in standard GCEA tuning. More ukulele shapes.
What key is B♭dim in?
In major keys, B♭dim is vii° in B major. In minor keys it is ii° in G♯ minor.
What's the difference between B♭dim and B♭m?
B♭dim and B♭m differ by one note: F♭ in B♭dim, F in B♭m. They share B♭ and D♭.
Every diagram on this page is generated from the notes B♭, D♭ and F♭ and checked automatically so the sound matches the drawing. Updated September 2026.