3 notes · 1 · ♭3 · ♭5

C# Diminished Piano Chord (C#dim)

C#dim is built from C#, E and G — the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above C#. The shape uses 2 white and 1 black key, and you can hear it, invert it and compare it below.

Root noteChord type

Chord

C# Diminished

Notes

C# · E · G

Formula

1 · ♭3 · ♭5

Right hand

1 · 3 · 5

Choose a chord, then play it. Finger numbers run from thumb (1) to little finger (5).

The finder above already holds C#dim. Press P or the Play chord button to hear C#, E, G sounded together, then change the root or the chord type to compare it with something else.

Chord tones

The notes in C#dim

A diminished triad is two minor thirds stacked on top of each other, which squeezes the fifth a semitone flat. The result is tense and unresolved. It appears on the seventh degree of a major scale and on the second degree of a minor key, and it usually leads straight back to a more stable chord.

Each tone of C# diminished with its interval, scale degree, distance in semitones from C# and a suggested right-hand finger.
Note	Interval	Degree	Semitones	Right hand
C#black key	Root	1	0	1 · thumb
Ewhite key	Minor third	♭3	3	3 · middle finger
Gwhite key	Diminished fifth	♭5	6	5 · little finger

Step by step

How to play C#dim on piano

Find C#: it is the first black key in a group of two.
Build upwards from C# using 3 and 6 semitones to reach E and G.
With the right hand, place finger 1 on C#, finger 3 on E and finger 5 on G. Keep the wrist level and the knuckles rounded.
Move your hand a little further in towards the fallboard so the black key sits comfortably under your fingers.
Play the notes together, then one at a time from the bottom up, and listen to how C#dim settles.
Try first inversion as well: E – G – C#. Inversions let you change chords without jumping around the keyboard.

Inversions

C#dim in 3 positions

An inversion keeps the same 3 notes and simply moves the lowest one up an octave. Learning them means you can change chords with small hand movements instead of jumping to a new part of the keyboard.

Root position

C# – E – G

The root C# is the lowest note. This is the shape most people learn first.

First inversion

E – G – C#

E is the lowest note, so the minor third sits in the bass and the notes below it move up an octave.

Second inversion

G – C# – E

G is the lowest note, so the diminished fifth sits in the bass and the notes below it move up an octave.

In context

Which keys contain C#dim

In D major the chord functions as vii°. Altogether it is produced by the scales of 3 keys, so learning it once pays off in several places.

D majorvii°
D harmonic minorvii°
B minorii°

Chord tones are spelled by the degree they occupy, so the third of a minor chord is written as a flat rather than a sharp even though it is the same key on the piano. A double sharp such as F## means the key one whole tone above F.

Compare

C#dim against C# minor

C#dim and C# minor share C# and E. Moving the perfect fifth G# down 1 semitone to the diminished fifth G turns C# minor into C#dim.

Practise the pair together: hold the shared notes C#, E still and move only the one finger. Hearing that single change is the quickest way to recognise the two chords by ear.

Open C# minor →

Good questions

C#dim questions

What notes are in the C#dim chord?

C#dim contains C#, E and G. Counted from the root, that is the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above C#.

What is the right-hand fingering for C#dim?

A comfortable beginner fingering is 1 (thumb) on C#, 3 (middle finger) on E and 5 (little finger) on G. Finger numbers run from the thumb (1) to the little finger (5), and they change once you start using inversions.

How is C#dim different from C# minor?

C#dim and C# minor share C# and E. Moving the perfect fifth G# down 1 semitone to the diminished fifth G turns C# minor into C#dim.

Which keys use the C#dim chord?

It occurs naturally in D major (vii°), D harmonic minor (vii°) and B minor (ii°). The roman numeral shows which degree of the key the chord is built on.

What are the inversions of C#dim?

root position is C# – E – G, first inversion is E – G – C# and second inversion is G – C# – E. Every inversion holds the same notes; only the lowest one changes.

Is C#dim the same as the D♭ chord?

On an equal-tempered piano C# and D♭ are the same key, so the chords sound identical. Written music chooses between them according to the key signature: pages here are named after the sharp spelling of the root, and the chord tones are then spelled by the degree each one occupies, which is why a double sharp occasionally appears.