C diminished chord (Cdim)
Cdim is C, E♭ and G♭: 1–♭3–♭5 built on C. Below: guitar, piano and ukulele, each playable.
On guitar
x-3-4-5-4-x · movable · medium
- Notes
- C · E♭ · G♭
- Formula
- 1 · ♭3 · ♭5
- First shape
- x-3-4-5-4-x
Cdim on guitar: every shape, finger by finger
On piano
root position · C–E♭–G♭ · right hand 1-3-5
- Notes
- C · E♭ · G♭
- Formula
- 1 · ♭3 · ♭5
Cdim on piano: fingering and inversions
On ukulele
5-3-2-3 · movable · medium
- Notes
- C · E♭ · G♭
- Formula
- 1 · ♭3 · ♭5
- First shape
- 5-3-2-3
Cdim and the chords around it
The moves below are the ones you'll meet most, shown for guitar and piano.
- Cdim → C♯ (leads up a half step)
Guitar: Cdim (x-3-4-5-4-x) to C♯ (x-4-6-6-6-4): the index finger lays across the A to high E strings at the 4th fret, move the middle finger to the D string, 6th fret, your ring finger lands on the G string, 6th fret. No finger can stay, so practice lifting all of them together and landing the new shape as a unit.
Piano: Cdim to C♯: play C♯ in root position (C♯–E♯–G♯), while C moves up to C♯, E♭ up to E♯ and G♭ up to G♯. C♯ - Cdim → C♯m (leads up a half step)
Guitar: Cdim (x-3-4-5-4-x) to C♯m (x-4-6-6-5-4): the index finger lays across the A to high E strings at the 4th fret, your middle finger lands on the B string, 5th fret, the ring finger goes to the D string, 6th fret. Everything moves: lift the whole hand and place the new shape in one go.
Piano: Cdim to C♯m: play C♯m in root position (C♯–E–G♯), while C moves up to C♯, E♭ up to E and G♭ up to G♯. C♯m - Cdim → Fm (iii in D♭ major)
Guitar: Cdim (x-3-4-5-4-x) to Fm (1-3-3-1-1-1): the index finger lays across the low E to high E strings at the 1st fret, move the middle finger to the A string, 3rd fret, your ring finger lands on the D string, 3rd fret. Everything moves: lift the whole hand and place the new shape in one go. The two chords share C, which is why the change sounds smooth.
Piano: Cdim to Fm: play Fm in 2nd inversion (C–F–A♭) and C stays under the same finger, while E♭ moves up to F and G♭ up to A♭. Fm
How Cdim is built
Cdim is a diminished triad: two minor thirds stacked. It sounds tense and unstable and rarely stays long. Its most common job is to lead up a half step, so Cdim usually moves to C♯ or C♯m.
Start on C, count 3 half steps up to E♭ then 3 half steps up to G♭.
| Note | Role | Half steps | Hear it |
|---|---|---|---|
| C | root | 0 | |
| E♭ | minor third | 3 | |
| G♭ | diminished fifth | 6 |
Keys and progressions with Cdim
You'll find Cdim as vii° in D♭ major. On the minor side it's ii° in B♭ minor.
Chords close to Cdim
- Cdim and Cm differ by one note: G♭ in Cdim, G in Cm. They share C and E♭. Cm
Chords that share most of their notes with Cdim: Cdim7, Cm7♭5, E♭m6, D♯dim7, F♯dim7, A♭7.
Every C chord
C diminished chord: questions
What notes are in the C diminished chord?
C, E♭ and G♭. Cdim is built 1–♭3–♭5 from C: E♭ is the minor third and G♭ is the diminished fifth.
How do you play Cdim on guitar?
The usual shape is x-3-4-5-4-x (movable). All 4 guitar shapes.
How do you play Cdim on piano?
Play C, E♭ and G♭ with right-hand fingers 1-3-5. C sits just left of the pair of black keys. Inversions and left hand.
How do you play Cdim on ukulele?
5-3-2-3 in standard GCEA tuning. More ukulele shapes.
What key is Cdim in?
You'll find Cdim as vii° in D♭ major. On the minor side it's ii° in B♭ minor.
What's the difference between Cdim and Cm?
Cdim and Cm differ by one note: G♭ in Cdim, G in Cm. They share C and E♭.
Every diagram on this page is generated from the notes C, E♭ and G♭ and checked automatically so the sound matches the drawing. Updated September 2026.