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The Cm7b5 chord (C half-diminished) on guitar

Cm7b5 is a Cm7 with one note pushed down a half step: the fifth, G, becomes Gb. That small change makes the chord dark and restless, a chord that does not want to stay where it is. Jazz players call it C half-diminished, and they use it for one main job: leading into a minor key.

Cm7b5 chord: notes and shapes at a glance

  • Name: C half-diminished (minor seventh flat five)
  • Symbol: Cm7b5
  • Notes: C, Eb, Gb, Bb
  • Where it belongs: viim7b5 in Db major, iim7b5 in Bb minor

Each shape below is written from the thickest string to the thinnest: a number is the fret, 0 an open string, x a string you do not play. New to this? See how to read chord diagrams.

Shape Frets, low E to high E Notes, low to high What it is for
Cm7b5, four strings xx1312 Eb Bb C Gb All four notes on the top strings. Eb is the lowest note, so use it when a bass player or another guitar holds the C.
Cm7b5, root on the A string x3434x C Gb Bb Eb The standard shape: four strings, four fingers, no barre. Movable to any half-diminished chord with its root on the fifth string.
Cm7b5, root on the low E 8x887x C Bb Eb Gb Root at fret 8 on the sixth string, fifth string muted. Dark and compact, the jazz comping voicing.
Cm7b5, four strings x x 1 3 1 2 · · 1 3 1 2 fingers
Cm7b5, root on the A string x 3 4 3 4 x · 2 3 1 4 · fingers
Cm7b5, root on the low E 8 x 8 8 7 x 2 · 3 4 1 · fingers

Read each diagram from the thickest string on the left to the thinnest on the right. A cross means the string is not played, a circle means it rings open.

Cm7b5 on the neck: every C, Eb, Gb, Bb

Standard tuning, frets 0 to 12. The highlighted notes are the notes of Cm7b5: any shape you build from them, anywhere on the neck, is still Cm7b5.

Fretboard notes
Swipe the fretboard sideways to see every fret.
0
1
2
3
4
5
6
7
8
9
10
11
12
1 - E
E
F
Gb
G
Ab
A
Bb
B
C
Db
D
Eb
E
2 - B
B
C
Db
D
Eb
E
F
Gb
G
Ab
A
Bb
B
3 - G
G
Ab
A
Bb
B
C
Db
D
Eb
E
F
Gb
G
4 - D
D
Eb
E
F
Gb
G
Ab
A
Bb
B
C
Db
D
5 - A
A
Bb
B
C
Db
D
Eb
E
F
Gb
G
Ab
A
6 - E
E
F
Gb
G
Ab
A
Bb
B
C
Db
D
Eb
E

How to play Cm7b5, step by step

The reference shape, x3434x, uses four strings and one finger per string. No barre.

  1. Second finger on the fifth string (A) at fret 3: C, the root.
  2. Third finger on the fourth string (D) at fret 4: Gb, the flat five. This is the note that makes the chord.
  3. First finger on the third string (G) at fret 3: Bb, the seventh.
  4. Fourth finger on the second string (B) at fret 4: Eb, the minor third.
  5. Mute both E strings. The first finger can touch the high E lightly, the tip of the second finger the low E.
Gb sits at the same fret as F#. It is written Gb because it is the fifth of C, lowered by a half step. The fretboard diagram above shows the same pitch under its everyday name.

Cm7, Cm7b5, Cdim7: three steps darker

Chord Notes What changes
Cm7 C, Eb, G, Bb The starting point: minor seventh, relaxed.
Cm7b5 C, Eb, Gb, Bb The fifth drops: half-diminished.
Cdim7 C, Eb, Gb, Bbb (played as A) The seventh drops too: fully diminished.

On the guitar, the first step is a single fret: play x35343 (Cm7), then x3434x. The D string goes from G at fret 5 to Gb at fret 4, and the mood changes completely.

The minor ii V i: Cm7b5, F7, Bbm

In a major key the ii chord is a minor seventh: Cm7, F7, Bbmaj7 in B flat. In a minor key the ii chord is half-diminished, and that is the job Cm7b5 does: Cm7b5, F7, Bbm resolves into B flat minor.

Chord Shape Role
Cm7b5 x3434x ii: the tension begins
F7 1x121x V: the tension peaks
Bbm x13321 i: home, in B flat minor

Play it slowly, four beats per chord, and listen to the Gb of Cm7b5: it becomes the F of F7, then stays as the F of B flat minor. The same move a whole step higher, Dm7b5, G7, Cm, leads into C minor. More of these are on the chord progressions page.

One shape, every half-diminished chord

x3434x has no open strings, so it moves anywhere on the neck. The root is always the note on the fifth string.

  • Bm7b5: x2323x
  • Cm7b5: x3434x
  • Dm7b5: x5656x, see the Dm7b5 chord

One more thing worth knowing: spelled from Eb, the notes of Cm7b5 are Eb, Gb, Bb, C, the notes of Ebm6. Which name applies depends on the bass and on the job the chord does in the song, exactly as Cm6 and Am7b5 share the same four notes.

Frequently asked questions

How do you play Cm7b5 on guitar?
Play x3434x: second finger on the fifth string (A) at fret 3, third finger on the fourth string (D) at fret 4, first finger on the third string (G) at fret 3, fourth finger on the second string (B) at fret 4. Leave both E strings silent.
What notes are in Cm7b5?
Four: C, Eb, Gb and Bb. The formula is 1, b3, b5, b7: a minor third, a diminished fifth and a minor seventh above C. Gb is played exactly where F# is on the neck; it is called Gb here because it is the fifth of C, lowered.
Is Cm7b5 the same as C half-diminished?
Yes. Cm7b5, C half-diminished and Cø7 (or Cø) are three names for the same chord. Half-diminished means a diminished triad (C, Eb, Gb) with a minor seventh (Bb) on top. A fully diminished seventh, Cdim7, lowers that seventh one more half step.
What is the difference between Cm7 and Cm7b5?
Only the fifth. Cm7 has G, Cm7b5 has Gb. On guitar you can hear it on one string: from x35343 to x3434x, the D string goes from G at fret 5 to Gb at fret 4. That half step turns a relaxed chord into an unstable one.
Where is Cm7b5 used?
Above all as the ii chord of a minor ii V i: Cm7b5, F7, Bbm, which resolves to B flat minor. It also appears as the vii chord of D flat major, and as a passing chord in jazz standards and bossa nova.
Yohann Abbou, guitar teacher and founder of Guitar Social Club

Who made this

Guitar Social Club is the work of Yohann Abbou, a guitar teacher in Paris who teaches adults. Every shape on this page is written string by string and checked against standard tuning, and the diagrams are drawn from those same fret numbers. The rest of our free guitar tools, including the chord finder, work the same way.

More about Yohann on his page, and about why Guitar Social Club exists.