Chord · 7ths

B♭dim7 — B♭ Diminished 7th

B♭dim7 is the B♭ diminished 7th chord. It is built on the root B♭ with minor 3rd (D♭), diminished 5th (F♭) and diminished 7th (A𝄫) above it — the formula 1 ♭3 ♭5 𝄫7, sounding the notes B♭ D♭ F♭ A𝄫. On the piano it sits at Bb (octave 3) and above in the library's voicing; the same 4 notes in any octave are still B♭dim7.

Root
B♭
Quality
Diminished 7th
Formula
1 ♭3 ♭5 𝄫7
Notes
B♭ D♭ F♭ A𝄫

On the keyboard

B♭dim7 on the piano keyboard: B♭ D♭ F♭ A𝄫1235B♭D♭F♭A𝄫

Right-hand fingering for this voicing: 1–2–3–5 (1 is the thumb).

The notes of B♭dim7

DegreeNoteInterval from the rootPitch
1B♭rootB♭3
♭3D♭minor 3rdD♭4
♭5F♭diminished 5thF♭4
𝄫7A𝄫diminished 7thA♭♭4

Other 7ths on B♭

Diminished 7th chords on every root

Part of the chord reference. See also the scales and the keys.