C half-diminished (Cm7b5) chord on piano

The C half-diminished chord (Cm7b5) is a half-diminished seventh chord (a diminished triad plus a minor seventh), made of four notes: C – E♭ – G♭ – B♭.

Root position: C4 – E♭4 – G♭4 – B♭4

Chord finder Transposer

What the Cm7b5 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 Cm7b5 chord

Degree	Note	Interval from the root
1	C	root
3	E♭	minor third (3 semitones)
5	G♭	diminished fifth (6 semitones)
7	B♭	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

C4 – E♭4 – G♭4 – B♭4

1st inversion

E♭4 – G♭4 – B♭4 – C5

2nd inversion

G♭4 – B♭4 – C5 – E♭5

3rd inversion

B♭4 – C5 – E♭5 – G♭5

Which keys is it in?

The Cm7b5 chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

D♭ major: viiø7
B♭ minor: iiø7

Similar chords and substitutes

If Cm7b5 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

A♭9 – a rootless dominant ninth: the same notes over a root a major third lower
F7 – the next chord in a minor ii–V–i (V)

Same notes

E♭m6 – the same notes with a different root

Simpler versions

Cdim – all 3 of its notes are in this chord

Frequently asked questions

What notes are in the Cm7b5 chord?

C, E♭, G♭, B♭. The root is C; the intervals of the other notes from the root: minor third, diminished fifth, minor seventh.

How do I play the Cm7b5 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.

How is the Cm7b5 chord written?

The chord symbol is Cm7b5, and its full name is C half-diminished.