Cdim Piano Chord

C diminished is the Cdim piano chord. It has three notes: C, E flat and G flat. It is a C minor chord with the fifth lowered by one key, which makes it sound tense rather than sad.

1C3E♭5G♭C4C5

C at the bottom, then E♭ and G♭. Right hand 1-3-5, left hand 5-3-1. The black keys are E♭ and G♭.

How to play Cdim on piano, step by step

  1. Start on middle C. That is the lowest note of the chord.
  2. Thumb (1): C
  3. Middle finger (3): E♭
  4. Little finger (5): G♭
  5. Press them together with the right hand. The left hand plays the same notes with fingers 5, 3, 1 an octave lower, or just C on its own as a bass note.

Both gaps in this chord are the same size, three keys each. That symmetry makes the hand shape easy to remember and easy to move: slide it up three keys and you have another diminished chord.

Inversions of Cdim

The same 3 notes with a different one at the bottom. All of them are Cdim; which you play depends on what the hand is coming from. Tap any card to hear it.

First inversionE♭ G♭ C
Cdim piano chord diagram, first inversion, E♭ G♭ C
Lighter than root position and less final. A flat third in the bass tips the chord forward, which is why it usually sits between two other chords rather than at the end of a line.
Second inversionG♭ C E♭
Cdim piano chord diagram, second inversion, G♭ C E♭
Open and slightly unresolved. A fifth in the bass makes the chord sound like a step on the way somewhere, which is mostly how it is used.

If it sounds wrong

The top note is G
That gives C minor. C diminished needs G flat, the black key one lower.
The chord sounds unstable
It is supposed to. Play C diminished then D flat major, or C diminished then C minor, and the tension resolves.
The black keys are uneven
E flat and G flat are both black and narrow. Aim each fingertip at the middle of its key.

What makes it a Cdim

C · E♭ · G♭ 1 ♭3 ♭5

C diminished is C, E flat and G flat: the root, the flat third and the flat fifth. Two minor thirds stacked, which is what makes every diminished chord symmetrical.

Its usual job is to lead somewhere. As a passing chord it slips between two others a step apart, and as a leading tone chord it climbs a half step to D flat.

Cdim vs Cm

The top note. C minor has G; C diminished has G flat, one key lower. Minor is settled sadness, diminished is unresolved tension.

Because the drop is only one key, the two chords sit under almost the same hand shape and are worth practising back to back.

Questions about Cdim

Which notes are in a Cdim chord on piano?

C, E flat and G flat. It is a minor chord with the fifth lowered by one key.

What is the difference between Cdim and C minor?

The top note. C minor has a normal fifth; Cdim lowers it by one key to G flat. That single change turns a sad chord into a tense one.

How does a diminished chord resolve?

Usually up by one key. Cdim leans toward D flat major, and playing the two in a row is the quickest way to hear why: every note of the diminished chord is a half step or a whole step from where it wants to go.

Is Cdim hard to play?

No. It is three notes with an even shape, since a diminished triad is two minor thirds stacked. The intervals are the same size, which makes the hand position symmetrical and easy to remember.

Chords to learn next

Other C chords