F#m7b5 F# half-diminished seventh chord
- Notes
- F# A C E
- Formula
- 1 b3 b5 b7
- Semitones
- 0 3 6 10 above the root
- Also written
- Gbm7b5 (Gb Bbb Dbb Fb)
- Other symbols
- F#ø7, F#ø, F#m7(b5), F#min7b5
F# to A is a minor third (3 semitones), A to C is a minor third (3 semitones), C to E is a major third (4 semitones). A diminished triad plus a minor seventh, E, so F# to C is a tritone. It is also called half-diminished: the fully diminished F#dim7 has a diminished seventh (9 semitones) instead. With A in the bass the same four keys read as Am6.
F#m7b5 on the piano
Root position from F#4: F#4, A4, C5, E5. Middle C is C4.
F#m7b5 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.
2 x 2 2 1 x (low E to high e)
Sounds F#2 E3 A3 C4
x 9 10 9 10 x (low E to high e)
Sounds F#3 C4 E4 A4
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 F#m7b5
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# A C E | F#m7b5 | |
| 1st inversion | A C E F# | Am6 (also read as F#m7b5/A) | |
| 2nd inversion | C E F# A | F#m7b5/C | |
| 3rd inversion | E F# A C | F#m7b5/E |
Where F#m7b5 fits
F#m7b5 is viiø7 in G major, iiø7 in E minor. As iiø7 it opens the minor ii–V–i: F#m7b5 → B7 → Em, the minor-key twin of the ii–V–I.