C Half Diminished
Hear the C Half Diminished chord played for you.
Cø7
C – E♭ – G♭ – B♭
Formula:R-m3-d5-m7
Intervals:P1-m3-d5-m7
Scale Degrees:1-b3-b5-b7
Introduction
The C Half Diminished chord is a four-note chord made up of C, E♭, G♭, and B♭. It is built from a root, minor third, diminished fifth, and minor seventh.
The C Half Diminished piano chord (Cm7b5) consists of the notes C, Eb, Gb, Bb. It is a diminished triad with an added minor 7th, giving it a dark, moody, and tense character commonly used in jazz and minor key progressions. Formula: R-m3-d5-m7 | Scale degrees: 1-b3-b5-b7.
Notes
C Half Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | C – E♭ – G♭ – B♭ |
| 1st Inversion | E♭ – G♭ – B♭ – C |
| 2nd Inversion | G♭ – B♭ – C – E♭ |
| 3rd Inversion | C – E♭ – G♭ – B♭ |
Key Signature
The key of C Half Diminished has no sharps or flats. Every note is natural, which makes it the easiest key signature to read on the staff.
Chords in the Key of C Major
These are the diatonic triads built on each degree of the C major scale:
C
D
E
F
G
A
B
C
D
E
F
G
A
B
I — C Major (major)
Theory: Intervals
Formula: R-m3-d5-m7
Intervals: P1-m3-d5-m7
The C Half Diminished is built by stacking intervals from the root note. The formula R-m3-d5-m7 describes the scale degrees used. The intervals P1-m3-d5-m7 show the distance between each note in the chord.
C Half Diminished — Frequently Asked Questions
What notes are in the C Half Diminished chord?
Cm7b5 contains four notes: C (root), Eb (minor third), Gb (diminished fifth), and Bb (minor seventh). A diminished triad with a minor seventh — dark, moody, and tense.
How does Cm7b5 differ from Cdim7?
Cm7b5 has Bb (minor seventh). Cdim7 has A (diminished seventh). Half-diminished is less tense than fully diminished — the minor seventh softens it slightly.
How does Cm7b5 differ from Cm7?
Cm7b5 has Gb (diminished fifth). Cm7 has G (perfect fifth). The flatted fifth adds significant tension and darkness.
How is Cm7b5 used in music?
Cm7b5 is the ii chord in Bb minor jazz harmony (Cm7b5–F7–Bbm). It is essential for minor-key ii–V–i progressions. Also the vii chord in Db Major.
What songs use Half Diminished chords?
Half-diminished chords are essential in jazz minor-key harmony. Autumn Leaves uses the ii°7–V7–i in G minor. Still Crazy After All These Years (Paul Simon) features half-diminished harmony.
Is Cm7b5 the same as Ebm6?
Same four notes (C, Eb, Gb, Bb = Eb, Gb, Bb, C). Context determines the name: Cm7b5 when C is root, Ebm6 when Eb is root.
Practice Tips
- The minor-key ii–V–i: Cm7b5 → F7 → Bbm is essential jazz vocabulary.
- Compare Cm7b5 with Cdim7 — minor seventh vs diminished seventh.
- Compare Cm7b5 with Cm7 — one note (Gb vs G) transforms smooth into tense.
- Cm7b5 and Ebm6 are the same notes — context determines the name.
- Half-diminished is the sound of minor-key jazz — learn it in all keys.
- The symbol ø (slash through the circle) means half-diminished.
Related Tools
Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.