Cdim7 guitar chord
The standard grips this chord is usually shown with.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About Cdim7 — 2nd inversion
Cdim7 is C, Eb, Gb and A — Cdim with a diminished seventh stacked on top.
It sounds suspenseful and rootless. Three stacked minor thirds divide the octave evenly, so the same four notes spell four dim7 chords and the shape repeats every three frets.
Cdim7 notes and formula
| C | Eb | Gb | A |
|---|---|---|---|
| 1 | ♭3 | ♭5 | ♭♭7 |
Leading-tone or passing chord — it can resolve almost anywhere.
Also written C°7, Co7 or C diminished 7. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Cdim7
Cdim7 in 2nd inversion puts Gb in the bass instead of C, the 5th of the chord. The notes are the same; what changes is what the bass line does, which is most of why you would reach for it — it lets the lowest voice move by step where the root would have jumped.
One of Cdim7’s 7 common shapes does this: xx4545.
Start with xx1212 — no barre and down at the nut. None of the shapes for Cdim7 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 2 of the 7 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| xx1212 | 1st fret | Eb, 1st inversion | Gb | all fretted |
| x34242 | 2nd fret | C, root position | Gb | all fretted |
| xx4545 | 4th fret | Gb, 2nd inversion | A | all fretted |
| 8x7878 | 7th fret | C, root position | C | barred |
| 8-9-10-8-10-8 | 8th fret | C, root position | C | barred |
| x-x-10-11-10-11 | 10th fret | C, root position | Eb | all fretted |
| x-x-13-14-13-14 | 13th fret | Eb, 1st inversion | Gb | all fretted |
The same notes rebuilt from scratch give 5 shell, 14 drop 2, 9 drop 3 and 1 open string voicings, each on its own page.
Tensions. A shell of Cdim7, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (D), the 11 (F), the b13 (Ab) and the maj7 (B).
How to use Cdim7
A diminished seventh divides the octave evenly, so Cdim7 has no single root and no single destination: it can lead to F or to Db, and it is the same four notes either way.
What to play over Cdim7
Every note of Cdim7 is in C diminished and C half-whole diminished.
Chords near Cdim7
Change one note of Cdim7 and you have Cdim (drop the sixth), Cm6 (the flat fifth becomes a fifth), Cm7b5 (the sixth becomes a flat seventh) or CmMaj7b5 (the sixth becomes a major seventh).
Cdim7 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On Cdim7’s sound and use this page follows Stefan Kostka, Dorothy Payne & Byron Almén, Tonal Harmony (McGraw-Hill, 8th ed., 2018). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.