C Diminished Seventh Chord

Chord Tones: C Diminished Seventh Chord

Symbol: dim7, °7 — Formula: 1-♭3-♭5-𝄫7

Chord Notation

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Harmonic Function

The C diminished seventh chord commonly functions as the tonic (I) in C major/minor. Its harmonic role varies by key — in major keys it provides extended harmonic tension.

The diminished seventh chord consists of four equally-spaced minor thirds, creating a symmetrical, highly dissonant chord. It is used as a dramatic pivot chord and in chromatic passing harmony. The C Diminished Seventh Chord specifically contains 4 notes: C, D♯, F♯, A (formula: 1-♭3-♭5-𝄫7). On piano, C-rooted chords sit entirely on white keys in their basic triad form, making them the first chords most students learn. Pop, folk, and singer-songwriter music heavily use C-rooted chords because open-position guitar voicings and piano shapes are immediately accessible.

Common Progressions

The C Diminished Seventh Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• viidim7-I
• sharpivdim7-V

Songs Featuring the Diminished Seventh Chord

Well-known songs where the C Diminished Seventh Chord — or this chord type — plays a prominent role:

• While My Guitar Gently Weeps – Beatles
• Georgia on My Mind – Ray Charles
• Sophisticated Lady – Duke Ellington

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Scales Containing the C Diminished Seventh Chord

These scales include the C Diminished Seventh Chord as a diatonic or characteristic chord: