The C Diminished 7th chord is a four-note chord made up of C, E♭, G♭, and B♭♭. It is built from a root, minor third, diminished fifth, and diminished seventh.
Construction
C Diminished 7th = Root + Minor 3rd + Diminished 5th + Major 6th = C · E♭ · G♭ · B♭♭
| Note | Interval | Degree |
|---|---|---|
| C | Root | 1 |
| E♭ | Minor 3rd | ♭3 |
| G♭ | Diminished 5th | ♭5 |
| B♭♭ | Major 6th | 6 |
C Diminished 7th Inversions
| Position | Notes |
|---|---|
| Root Position | C – E♭ – G♭ – B♭♭ |
| 1st Inversion | E♭ – G♭ – B♭♭ – C |
| 2nd Inversion | G♭ – B♭♭ – C – E♭ |
| 3rd Inversion | B♭♭ – C – E♭ – G♭ |
Key Signature
A Diminished 7th chord is built from symmetrical or ambiguous intervals, so it doesn’t belong to a single key and has no key signature of its own.
Same Notes, Other Names
The notes C – E♭ – G♭ – B♭♭ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell the following:
C Diminished 7th — Frequently Asked Questions
What is the C Diminished 7th chord on piano?
The C Diminished 7th chord contains the notes C – E♭ – G♭ – B♭♭. On piano, play these notes together to sound the chord.
What notes are in the C Diminished 7th chord?
The C Diminished 7th chord (Cdim7) contains four notes: C (root), Eb (minor third), Gb (diminished fifth), and A (diminished seventh, enharmonically Bbb). All four notes are spaced exactly 3 semitones apart, making this a perfectly symmetrical chord.
How does C Diminished 7th differ from C Diminished?
C Diminished is a three-note triad (C, Eb, Gb). C Diminished 7th adds a fourth note — A (diminished seventh). This extra note completes the symmetrical structure and increases the harmonic tension. Dim7 is used far more often than the bare diminished triad, especially in jazz and classical.
Why is the Diminished 7th chord symmetrical?
Every note in Cdim7 is exactly 3 semitones from the next: C–Eb (3), Eb–Gb (3), Gb–A (3), A–C (3). This means there are only three unique diminished 7th chords — Cdim7, C#dim7, and Ddim7 — and every other dim7 is an inversion of one of these three.
How is C Diminished 7th used in music?
Cdim7 most commonly functions as a passing chord between two diatonic chords a whole step apart, or as a leading-tone chord resolving up by half step. In classical music it creates dramatic tension; in jazz it enables smooth chromatic voice leading between chords.
What songs use Diminished 7th chords?
Diminished 7th chords appear in Michelle (Beatles) as a chromatic passing chord, in classical music by Chopin, Beethoven, and Bach for dramatic effect, and throughout jazz standards for chromatic approach and passing movement. Silent film scores used dim7 chords extensively for suspense.
How many unique Diminished 7th chords exist?
Only three. Because of the perfect symmetry (equal 3-semitone spacing), every dim7 chord has three other enharmonic names. Cdim7 = Ebdim7 = Gbdim7 = Adim7 — they are all the same four notes rearranged. This means all 12 roots map to just three distinct sounds.