B Diminished 7th
Bdim7
Notes
B · D · F · A♭
Intervals
- RootB (1P)
- Minor 3rdD (3m)
- Diminished 5thF (5d)
- Diminished 7thA♭ (7d)
Fretboard
Adjust labels, frets, and palette in the interactive view.
Voicings & shapes
Drop-3 voicings (8)
Shell voicings (2)
Dim7 symmetrical (3)
One shape moved up 3 frets gives the next enharmonic root: C, E♭, G♭, and A dim7 are the same four notes.
About
The B fully diminished 7 (B–D–F–A♭) stacks four minor thirds, giving it a fully symmetrical structure. Each note can be respelled as a root — B°7 is enharmonically the same chord as D°7, F°7, and A♭°7 — meaning a single shape on the guitar can function as four different leading-tone chords depending on context. This flexibility makes dim7 especially useful as a passing or substitution chord, often resolving up a half step (here to C). All four tones carry the chord’s identity; the chord is defined by its symmetry, so removing any note weakens that quality. On guitar, one shape repeats identically every three frets. Compared to Bm7♭5, dim7 is more unstable and dramatically tense.
Chord diagrams
B Diminished 7th voicing charts — tap a sheet to open it full size to save or print.
Similar chords
Chords sharing two or more notes with this one, ranked by overlap.
Scales containing this chord
- B Diminished (deg 1)
- A Diminished (deg 2)
- A Harmonic Minor (II)
- A♭ Diminished (deg 3)
- C Diminished (deg 8)
- C Harmonic Minor (VII)
- D Diminished (deg 7)
- E♭ Diminished (deg 6)
- E♭ Harmonic Minor (VI)
- F Diminished (deg 5)
- F♯ Diminished (deg 4)
- F♯ Harmonic Minor (IV)
Scales whose notes include every chord tone. The Roman numeral (or scale degree) marks the chord root’s position in the scale.