G#m7b5 Chord on Guitar
G#m7b5 = G# – B – D – F# (Root, Minor 3rd, Tritone, Minor 7th)
G#m7b5, or half-diminished, lowers the fifth of G#m7 by a half step, landing between the smooth consonance of a plain minor seventh and the fully unstable dissonance of a diminished seventh — diminished in one respect, not all the way.
G#-B-D-F#: root, minor third, diminished fifth, and minor seventh. That lowered fifth on an otherwise ordinary minor-seventh structure is the signature sound of the ii chord in minor-key jazz harmony — G#m7b5 is exactly the chord a minor ii-V-i progression needs when the key center is F# minor, replacing the plain minor seventh a major-key ii-V would use with this darker, more tension-laden version.
Fingerings
Barre (4th fret)
How to Practice It
This shape uses a slightly different finger arrangement than the straightforward major or minor barres in this family since the altered fifth changes the muted or repositioned strings — take it slowly, isolating the fifth's new position before strumming the whole chord. Practice it inside a ii-V-i in F# minor (G#m7b5 – C#7 – F#m) to hear why this chord exists rather than a plain G#m7.
Common Progressions
- G#m7b5 – C#7 – F#m (ii – V7 – i, the classic minor-key jazz turnaround)
- G#m7b5 – C#7 – F#m – Bm (a fuller minor ii-V-i moving on to iv)
- E – G#m7b5 – C#7 (a color move using the half-diminished chord as an unsettled pivot before resolving)
- F#m – G#m7b5 – C#7 – F#m (i – ii – V7 – i, a compact minor-key loop)
FAQ
- What does 'half-diminished' mean for G#m7b5?
- It shares the diminished triad's lowered fifth but keeps a regular minor seventh rather than the fully diminished seventh a true dim7 chord uses, landing it harmonically between the two in terms of tension.
- Where does G#m7b5 typically appear?
- As the ii chord in a minor-key ii-V-i progression — most commonly in F# minor, where it leads into C#7 and then resolves to F#m, mirroring the role a plain minor seventh ii chord plays in major-key jazz harmony.
- How does G#m7b5 differ from G#dim7?
- G#dim7 lowers both the fifth and the seventh, giving a fully symmetrical, more starkly tense chord, while G#m7b5 only lowers the fifth and keeps an ordinary minor seventh, making it noticeably less dissonant.
- Is G#m7b5 common outside jazz contexts?
- It appears far more often in jazz and jazz-influenced writing than in straightforward pop or rock, since minor ii-V-i progressions are themselves a specifically jazz harmonic device.
- Is this chord ever written as Abm7b5?
- Yes, under flat-key spelling, though the fingering and pitches remain identical to G#m7b5 regardless of which name is used.
G#m7b5 on other instruments: G#m7b5 on Piano. Related: how chords are built, chord finder.