A♯dim7 (diminished seventh) / B♭dim7 (diminished seventh)

4-note diminished 7th on A♯ / B♭A♯, C♯, E, G.

Press to hear the chord strummed low to high.

Three stacked minor thirds — perfectly symmetric, so every note could be the root. A classic pivot chord.

The notes

Pitches taken from the first fingering below — click any note to open its frequency page.

Interval formula

DegreeNoteWhat it is
1A♯root
♭3C♯minor third
♭5Eflat fifth (diminished)
6Gmajor sixth

The formula reads in semitones above the root (A♯): 1, ♭3, ♭5, 6. A voicing may leave a tone out — often the fifth — but never adds one from outside this set.

Guitar fingerings · 4

123
open position
1324
open position
6fr123141
from fret 6
8fr1324
from fret 8

Ukulele fingerings · 4

12
open position
1324
open position
6fr1324
from fret 6
9fr1324
from fret 9

Read a diagram top-down: the thick bar is the nut, dots are where to press (the number is which finger), means play the open string, means don't play it. A bar across strings is a barre.

Other A♯ / B♭ chords

dim7 (diminished seventh) chords on every root