C diminished seventh (Cdim7) chord on piano

The C diminished seventh chord (Cdim7) is a diminished seventh chord (three stacked minor thirds), made of four notes: C – E♭ – G♭ – B𝄫.

Root position: C4 – E♭4 – G♭4 – B𝄫4

Chord finder Transposer

What the Cdim7 chord sounds like

A diminished seventh is three stacked minor thirds, so it is symmetrical: four different roots give the same notes. A dramatic, tense passing chord.

Notes of the Cdim7 chord

Degree	Note	Interval from the root
1	C	root
3	E♭	minor third (3 semitones)
5	G♭	diminished fifth (6 semitones)
7	B𝄫	diminished seventh (9 semitones)

Root position and inversions

An inversion uses the same notes, with a different note at the bottom. When you change chords, choosing the nearest inversion keeps your hand almost still.

Root position

C4 – E♭4 – G♭4 – B𝄫4

1st inversion

E♭4 – G♭4 – B𝄫4 – C5

2nd inversion

G♭4 – B𝄫4 – C5 – E♭5

3rd inversion

B𝄫4 – C5 – E♭5 – G♭5

Similar chords and substitutes

If Cdim7 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

A♭7 – an incomplete dominant: the diminished chord is the top of this seventh chord
C♯ – where it leads (leading tone → root)

Same notes

E♭dim7 – the same notes with a different root
F♯dim7 – the same notes with a different root
Adim7 – the same notes with a different root

Simpler versions

Cdim – all 3 of its notes are in this chord

Frequently asked questions

What notes are in the Cdim7 chord?

C, E♭, G♭, B𝄫. The root is C; the intervals of the other notes from the root: minor third, diminished fifth, diminished seventh.

How do I play the Cdim7 chord on piano?

In root position, the right hand usually plays with fingers 1, 3 and 5 (thumb, middle finger, little finger); four-note chords with fingers 1, 2, 3 and 5. The left hand mirrors this: 5, 3, 1. In an inversion the top or bottom note moves to the other side, so your hand moves less when you change chords.

How is the Cdim7 chord written?

The chord symbol is Cdim7, and its full name is C diminished seventh.