What notes are in the Cdim7 chord?

Cdim7 is made of C, Eb, Gb and A — the 1, b3, b5 and bb7 degrees of a diminished seventh chord built on C.

What keys use the Cdim7 chord?

No major or natural-minor key contains all 4 notes of Cdim7. Chords like this arrive as borrowed harmony — secondary dominants, harmonic-minor colour, or chromatic passing chords — rather than as one of a key's native chords.

How do you play Cdim7 on guitar and piano?

This page shows Cdim7 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.

Chord · C Diminished 7th

Cdim7 Chord

Cdim7 is C, Eb, Gb and A — symmetrical; passes through every key. Used as a dominant substitute.

Hear it

Cdim7 on every instrument

The same 4 notes, 6 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.

What Cdim7 is made of

Cdim7 (C diminished seventh) is built from the notes C, Eb, Gb, A, with the interval pattern 1, b3, b5, bb7.

Stack 1, b3, b5 and bb7 on a root of C and you get C, Eb, Gb and A. That interval recipe is what makes the chord a diminished seventh chord — move the same shape to another root and the character travels with it, which is why Ddim7 sounds like a transposed Cdim7.

Diminished 7th: Symmetrical; passes through every key. Used as a dominant substitute.

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 E♭ rather than its enharmonic equivalent.

Keys that contain Cdim7

No major or natural-minor key contains all 4 of these notes — this one gets borrowed.

Chords like this one sit outside the diatonic set — they arrive as secondary dominants, borrowed chords or passing harmony. Browse every key to see which progressions pull it in.

Other chords on C

Same root, different colour.

CC Major CmC Minor CdimC Diminished CaugC Augmented Csus2C Suspended 2nd Csus4C Suspended 4th C5C Power Chord C6C Major 6th

The same diminished seventh shape, moved

The identical interval recipe, built on other roots.

Ddim7D Diminished 7th Edim7E Diminished 7th Fdim7F Diminished 7th Gdim7G Diminished 7th Adim7A Diminished 7th Bdim7B Diminished 7th C♯dim7C# Diminished 7th F♯dim7F# Diminished 7th

Questions people ask about Cdim7

What notes are in the Cdim7 chord?: Cdim7 is made of C, Eb, Gb and A — the 1, b3, b5 and bb7 degrees of a diminished seventh chord built on C.
What keys use the Cdim7 chord?: No major or natural-minor key contains all 4 notes of Cdim7. Chords like this arrive as borrowed harmony — secondary dominants, harmonic-minor colour, or chromatic passing chords — rather than as one of a key's native chords.
How do you play Cdim7 on guitar and piano?: This page shows Cdim7 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.

Learn the theory behind it

Why Cdim7 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