What notes make up F#m7b5 on piano?

F# anchors F#m7b5 as the root, with A, C, E completing the half-diminished 7th formula above it — together, F#, A, C, E. That's root position; inversions just change which of those notes lands lowest.

Can F#m7b5's 4 notes be split between the hands instead of played together?

In most cases, yes, one hand covers it comfortably — but splitting the root off to the left hand is common practice too, not a sign you're doing it wrong.

What's the closest related chord to F#m7b5?

Raise the flatted 5th back up a half step and F#m7b5 becomes a plain minor 7th chord — the lowered 5th is what pushes it from merely mellow into genuinely unstable.

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F#m7b5 Chord on Piano

F#m7b5 = F# – A – C – E (Root, Minor 3rd, Tritone, Minor 7th)

Stack the half-diminished 7th formula on F# and you land on F#-A-C-E, a chord that sounds the tensest 'minor-family' chord in common use. F# itself is the first black key of the three-black-key group on the keyboard. Grabbed as a single root-position block, F#m7b5 ends up a sub-octave stretch in root position, which is well within a normal one-hand reach. Functionally this is the half-diminished viiø7 in G major, or the iiø7 chord that opens a minor-key ii–V–i, and the flatted 5th removes the stable perfect fifth a minor 7th chord would otherwise have, so it almost always keeps moving toward a dominant chord next. With the root counted in, the full chord runs to 4 notes, a figure worth having ready when reading any written voicing.

Think of F#m7b5 primarily as the half-diminished viiø7 in G major, or the iiø7 chord that opens a minor-key ii–V–i — that's what it's doing most of the time, in a lead sheet or in the moment. Put A on the bottom instead of F# and you've got first inversion; four-note chords like this one get used in inversion at least as often as they get used in root position. This shape asks nothing unusual of the hand in terms of span, which means the fastest path to fluency is simple repetition hands-separately before combining with a bass line. It shows up regularly in bossa nova minor progressions, and again in classical half-diminished passing chords. The flatted 5th removes the stable perfect fifth a minor 7th chord would otherwise have, so it almost always keeps moving toward a dominant chord next. Since first black key of the three-black-key group, a black-key root asks the hand to angle slightly forward, a small adjustment that stops feeling foreign after enough repetition. With low end already covered by a bass instrument, keep the left hand light — root, maybe the 7th — and let the right hand's upper notes do the harmonic work. Where you place this shape on the keyboard changes its character more than almost anything else you could do to it — low and it punches like bass, high and it turns delicate. Recognizing F#m7b5 by ear usually comes down to that the tensest 'minor-family' chord in common use character sticking in memory, faster than memorizing the actual note names ever does.

Voicings

Root Position

First Inversion

How to Practice It

Isolate the right-hand shape first: fingers whichever of 1-2-3-5 or 1-2-4-5 keeps your wrist level; both are standard choices for this shape over F#-A-C-E, played as a block chord until it's reliable without looking. Because F# is a black key, keep the hand slightly forward on the keybed rather than flat, or the black key will feel harder to press evenly with the rest of the chord. Next, add a simple left-hand root (whole notes, then quarter notes) underneath, and only after that combine both hands. Loop F#m7b5 against the chord that comes right before it in a real progression so your hand learns the physical jump, not just the shape in isolation. Slow, deliberate repetition beats fast sloppy repetition here — speed comes later. It's easy to confuse this with a plain minor 7th at a glance; the flatted 5th is the one note that makes the whole chord function differently, so isolate and check it specifically.

Common Progressions

iiø7 – V7 – i: F#m7b5 opening a minor ii–V–i in E minor
viiø7 – I: F#m7b5 resolving up a half step into G major
F#m7b5 as a dark pre-dominant chord just before the V7 in a minor key

FAQ

What notes make up F#m7b5 on piano?: F# anchors F#m7b5 as the root, with A, C, E completing the half-diminished 7th formula above it — together, F#, A, C, E. That's root position; inversions just change which of those notes lands lowest.
Can F#m7b5's 4 notes be split between the hands instead of played together?: In most cases, yes, one hand covers it comfortably — but splitting the root off to the left hand is common practice too, not a sign you're doing it wrong.
What role does F#m7b5 tend to fill in a chart?: The short answer: the half-diminished viiø7 in G major, or the iiø7 chord that opens a minor-key ii–V–i. The flatted 5th removes the stable perfect fifth a minor 7th chord would otherwise have, so it almost always keeps moving toward a dominant chord next.
What's the closest related chord to F#m7b5?: Raise the flatted 5th back up a half step and F#m7b5 becomes a plain minor 7th chord — the lowered 5th is what pushes it from merely mellow into genuinely unstable.

F#m7b5 on other instruments: F#m7b5 on Guitar. Related: how chords are built, chord finder.