Gm7b5 G half-diminished seventh chord
- Notes
- G Bb Db F
- Formula
- 1 b3 b5 b7
- Semitones
- 0 3 6 10 above the root
- Other symbols
- Gø7, Gø, Gm7(b5), Gmin7b5
G to Bb is a minor third (3 semitones), Bb to Db is a minor third (3 semitones), Db to F is a major third (4 semitones). A diminished triad plus a minor seventh, F, so G to Db is a tritone. It is also called half-diminished: the fully diminished Gdim7 has a diminished seventh (9 semitones) instead. With Bb in the bass the same four keys read as Bbm6.
Gm7b5 on the piano
Root position from G4: G4, Bb4, Db5, F5. Middle C is C4.
Gm7b5 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 G as its lowest note.
3 x 3 3 2 x (low E to high e)
Sounds G2 F3 Bb3 Db4
x 10 11 10 11 x (low E to high e)
Sounds G3 Db4 F4 Bb4
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 Gm7b5
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 | G Bb Db F | Gm7b5 | |
| 1st inversion | Bb Db F G | Bbm6 (also read as Gm7b5/Bb) | |
| 2nd inversion | Db F G Bb | Gm7b5/Db | |
| 3rd inversion | F G Bb Db | Gm7b5/F |
Where Gm7b5 fits
Gm7b5 is viiø7 in Ab major, iiø7 in F minor. As iiø7 it opens the minor ii–V–i: Gm7b5 → C7 → Fm, the minor-key twin of the ii–V–I.