Fm7b5 F half-diminished seventh chord
- Notes
- F Ab Cb Eb
- Formula
- 1 b3 b5 b7
- Semitones
- 0 3 6 10 above the root
- Other symbols
- Fø7, Fø, Fm7(b5), Fmin7b5
F to Ab is a minor third (3 semitones), Ab to Cb is a minor third (3 semitones), Cb to Eb is a major third (4 semitones). A diminished triad plus a minor seventh, Eb, so F to Cb is a tritone. It is also called half-diminished: the fully diminished Fdim7 has a diminished seventh (9 semitones) instead. With Ab in the bass the same four keys read as Abm6.
Fm7b5 on the piano
Root position from F4: F4, Ab4, Cb5, Eb5. Middle C is C4.
Fm7b5 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 F as its lowest note.
1 x 1 1 0 x (low E to high e)
Sounds F2 Eb3 Ab3 Cb4
x 8 9 8 9 x (low E to high e)
Sounds F3 Cb4 Eb4 Ab4
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 Fm7b5
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 | F Ab Cb Eb | Fm7b5 | |
| 1st inversion | Ab Cb Eb F | Abm6 (also read as Fm7b5/Ab) | |
| 2nd inversion | Cb Eb F Ab | Fm7b5/B | |
| 3rd inversion | Eb F Ab Cb | Fm7b5/Eb |
Where Fm7b5 fits
Fm7b5 is viiø7 in Gb major, iiø7 in Eb minor. As iiø7 it opens the minor ii–V–i: Fm7b5 → Bb7 → Ebm, the minor-key twin of the ii–V–I.