F#m7b5 Chord on Guitar
F#m7b5 = F# – A – C – E (Root, Minor 3rd, Tritone, Minor 7th)
F#m7b5, often called half-diminished, lowers the fifth of F#m7 by a half step, landing between the smooth consonance of a plain minor seventh and the fully unstable dissonance of a diminished seventh — hence the name, a chord that's diminished in one respect but not all the way.
F#-A-C-E: root, minor third, diminished fifth, and minor seventh. That combination of a lowered fifth with an otherwise ordinary minor-seventh structure is the signature sound of the ii chord in minor-key jazz harmony — F#m7b5 is exactly the chord a minor ii-V-i progression needs when the key center is E minor, replacing the plain minor seventh a major-key ii-V would use with this darker, more tension-laden version.
Fingerings
Barre (2nd fret)
How to Practice It
This shape uses a slightly different finger arrangement than most of the other barres in this family since the muted or repositioned strings don't follow the same pattern as a straightforward major or minor chord — take it slowly, isolating the fifth's altered position before trying to strum the whole thing at tempo. Practice it specifically inside a ii-V-i in E minor (F#m7b5 – B7 – Em) to hear why this chord exists rather than a plain F#m7: the lowered fifth intensifies the pull toward the dominant that follows.
Common Progressions
- F#m7b5 – B7 – Em (ii – V7 – i, the classic minor-key jazz turnaround)
- F#m7b5 – B7 – Em – Am (a fuller minor ii-V-i moving on to iv)
- D – F#m7b5 – B7 (a color move using the half-diminished chord as an unsettled pivot before resolving)
- Em – F#m7b5 – B7 – Em (i – ii – V7 – i, a compact minor-key loop)
FAQ
- What does 'half-diminished' mean for F#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 F#m7b5 typically appear?
- As the ii chord in a minor-key ii-V-i progression — most commonly in E minor, where it leads into B7 and then resolves to Em, mirroring the role a plain minor seventh ii chord plays in major-key jazz harmony.
- How does F#m7b5 differ from F#dim7?
- F#dim7 lowers both the fifth and the seventh, giving a fully symmetrical, more starkly tense chord, while F#m7b5 only lowers the fifth and keeps an ordinary minor seventh, making it noticeably less dissonant.
- Is F#m7b5 a common chord outside of jazz?
- 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 rather than a rock or pop staple.
- Is F#m7b5 hard to fret?
- It's a somewhat less intuitive shape than the plain major or minor barres since the altered fifth changes the finger pattern, but it's compact and low on the neck, so with some dedicated practice it becomes comfortable fairly quickly.
F#m7b5 on other instruments: F#m7b5 on Piano. Related: how chords are built, chord finder.