Chord · 7ths

C♯dim7 — C♯ Diminished 7th

C♯dim7 is the C♯ diminished 7th chord. It is built on the root C♯ with minor 3rd (E), diminished 5th (G) and diminished 7th (B♭) above it — the formula 1 ♭3 ♭5 𝄫7, sounding the notes C♯ E G B♭. On the piano it sits at C# (octave 4) and above in the library's voicing; the same 4 notes in any octave are still C♯dim7.

Root
C♯
Quality
Diminished 7th
Formula
1 ♭3 ♭5 𝄫7
Notes
C♯ E G B♭

On the keyboard

C♯dim7 on the piano keyboard: C♯ E G B♭1235C♯EGB♭

Right-hand fingering for this voicing: 1–2–3–5 (1 is the thumb).

The notes of C♯dim7

DegreeNoteInterval from the rootPitch
1C♯rootC♯4
♭3Eminor 3rdE4
♭5Gdiminished 5thG4
𝄫7B♭diminished 7thB♭4

Other 7ths on C♯

Diminished 7th chords on every root

Part of the chord reference. See also the scales and the keys.