Bm7b5 B half-diminished seventh chord
- Notes
- B D F A
- Formula
- 1 b3 b5 b7
- Semitones
- 0 3 6 10 above the root
- Other symbols
- Bø7, Bø, Bm7(b5), Bmin7b5
B to D is a minor third (3 semitones), D to F is a minor third (3 semitones), F to A is a major third (4 semitones). A diminished triad plus a minor seventh, A, so B to F is a tritone. It is also called half-diminished: the fully diminished Bdim7 has a diminished seventh (9 semitones) instead. With D in the bass the same four keys read as Dm6.
Bm7b5 on the piano
Root position from B4: B4, D5, F5, A5. Middle C is C4.
Bm7b5 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has B as its lowest note.
x 2 3 2 3 x (low E to high e)
Sounds B2 F3 A3 D4
7 x 7 7 6 x (low E to high e)
Sounds B2 A3 D4 F4
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play half-diminished seventh chords on other roots.
Inversions of Bm7b5
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | B D F A | Bm7b5 | |
| 1st inversion | D F A B | Dm6 (also read as Bm7b5/D) | |
| 2nd inversion | F A B D | Bm7b5/F | |
| 3rd inversion | A B D F | Bm7b5/A |
Where Bm7b5 fits
Bm7b5 is viiø7 in C major, iiø7 in A minor. As iiø7 it opens the minor ii–V–i: Bm7b5 → E7 → Am, the minor-key twin of the ii–V–I.