B♭ half-diminished (B♭m7b5) chord on piano

Looking for the B♭m7b5 chord on piano? It is a half-diminished seventh chord (a diminished triad plus a minor seventh), made of four notes: B♭ – D♭ – F♭ – A♭. The same chord with a different spelling: A♯ half-diminished (A♯m7b5).

Root position: B♭3 – D♭4 – F♭4 – A♭4

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What the B♭m7b5 chord sounds like

The half-diminished (m7b5) chord is a diminished triad with a minor seventh. In a minor key it sits on degree ii – the first chord of the minor ii–V–i.

Notes of the B♭m7b5 chord

Degree	Note	Interval from the root
1	B♭	root
3	D♭	minor third (3 semitones)
5	F♭	diminished fifth (6 semitones)
7	A♭	minor seventh (10 semitones)

Root position and inversions

An inversion uses the same notes, with a different note at the bottom. When you change chords, choosing the nearest inversion keeps your hand almost still.

Root position

B♭3 – D♭4 – F♭4 – A♭4

1st inversion

D♭4 – F♭4 – A♭4 – B♭4

2nd inversion

F♭4 – A♭4 – B♭4 – D♭5

3rd inversion

A♭4 – B♭4 – D♭5 – F♭5

Similar chords and substitutes

If B♭m7b5 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

F♯9 – a rootless dominant ninth: the same notes over a root a major third lower
E♭7 – the next chord in a minor ii–V–i (V)

Same notes

C♯m6 – the same notes with a different root

Simpler versions

B♭dim – all 3 of its notes are in this chord

Frequently asked questions

What notes are in the B♭m7b5 chord?

B♭, D♭, F♭, A♭. The root is B♭; the intervals of the other notes from the root: minor third, diminished fifth, minor seventh.

How do I play the B♭m7b5 chord on piano?

In root position, the right hand usually plays with fingers 1, 3 and 5 (thumb, middle finger, little finger); four-note chords with fingers 1, 2, 3 and 5. The left hand mirrors this: 5, 3, 1. In an inversion the top or bottom note moves to the other side, so your hand moves less when you change chords.

Why do some songbooks write H instead of B?

In German and Central European notation, H is the note B, and B is the note B♭. So a “B” chord in a German or Hungarian songbook is B♭ in English notation, and an “H” chord is B. Always check which notation your chord chart uses.