What notes are in the C#dim chord?

C#dim is made of C#, E and G — the 1, b3 and b5 degrees of a diminished chord built on C#.

What keys use the C#dim chord?

Every note of C#dim belongs to 2 keys: D Major (vii°), B Minor (ii°). The roman numeral is the scale degree the chord is rooted on.

How do you play C#dim on guitar and piano?

This page shows C#dim on guitar, piano, ukulele, bass, mandolin and banjo — 9 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.

Is C#dim the same as Dbdim?

Yes. C#dim and Dbdim are enharmonic — identical pitches written two different ways. Which spelling you use depends on the key you are in; C#dim is the spelling this site treats as canonical.

Chord · C# Diminished

C♯dim Chord

C♯dim is C#, E and G — tense, unstable; resolves outward.

Hear it

C♯dim on every instrument

The same 3 notes, 6 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.

What C♯dim is made of

C# Diminished (C# diminished) is built from the notes C#, E, G, with the interval pattern 1, b3, b5. A common diminished chord across many styles.

Stack 1, b3 and b5 on a root of C♯ and you get C#, E and G. That interval recipe is what makes the chord a diminished chord — move the same shape to another root and the character travels with it, which is why Cdim sounds like a transposed C♯dim.

Diminished: Tense, unstable; resolves outward.

Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with C♯ rather than its enharmonic equivalent.

Keys that contain C♯dim

All 3 notes sit inside the scale of 2 keys. The roman numeral marks the degree the chord is rooted on.

Major keys

D MajorC♯dim is the vii°

Minor keys

B MinorC♯dim is the ii°

Other chords on C♯

Same root, different colour.

C♯mC# Minor C♯m6C# Minor 6th C♯m7C# Minor 7th C♯m(maj7)C# Minor-Major 7th C♯dim7C# Diminished 7th C♯m7♭5C# Half-Diminished 7th (m7♭5)C♯m9C# Minor 9th C♯m/♭3C# Minor (1st Inversion)

The same diminished shape, moved

The identical interval recipe, built on other roots.

CdimC Diminished DdimD Diminished EdimE Diminished FdimF Diminished GdimG Diminished AdimA Diminished BdimB Diminished F♯dimF# Diminished

Questions people ask about C#dim

What notes are in the C#dim chord?: C#dim is made of C#, E and G — the 1, b3 and b5 degrees of a diminished chord built on C#.
What keys use the C#dim chord?: Every note of C#dim belongs to 2 keys: D Major (vii°), B Minor (ii°). The roman numeral is the scale degree the chord is rooted on.
How do you play C#dim on guitar and piano?: This page shows C#dim on guitar, piano, ukulele, bass, mandolin and banjo — 9 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
Is C#dim the same as Dbdim?: Yes. C#dim and Dbdim are enharmonic — identical pitches written two different ways. Which spelling you use depends on the key you are in; C#dim is the spelling this site treats as canonical.

Learn the theory behind it

Why C♯dim behaves the way it does — the guides that explain the chord instead of just spelling it.

Functional Harmony: Three Roles, One EngineDiminished chords are almost always doing a job. This explains which one.6 min read Cadences — The Four Ways a Phrase EndsWhere all that tension goes — how the chord resolves into the next one.4 min read Voice Leading — Hold What You Can, Move Only What You MustHalf-steps do the work here. Voice leading is how you find them.6 min read