Cdim chord
C diminished. The diminished triad: a minor third and a diminished fifth above the root. Built from two minor thirds, it sounds tense and unstable.
Click a note to hear it
- Notes
- C E♭ G♭
- Formula
- 1 ♭3 ♭5
- Intervals
- P1 m3 d5
- Also written
- C° · Co
Notes in Cdim
Cdim is spelled C E♭ G♭: three notes stacked from the root C.
| Note | Interval above C | Role | Formula |
|---|---|---|---|
| P1 | root | 1 | |
| m3 | third | ♭3 | |
| d5 | fifth | ♭5 |
Inversions
Putting a different chord tone in the bass gives each inversion. The chord is the same; the bass note changes how it sounds and what it can lead to.
| Position | Notes, low to high | Symbol | Hear it |
|---|---|---|---|
| Root position | C E♭ G♭ | Cdim | |
| First inversion | E♭ G♭ C | Cdim/E♭ | |
| Second inversion | G♭ C E♭ | Cdim/G♭ |
On the piano
The root position voicing, with every chord tone lit in its own colour. Click a key to hear it.
On the guitar
Cdim in standard tuning. The barre shapes below slide anywhere on the neck, so the same fingers give you every root. Strings run from the lowest (left) to the highest (right); X means do not play that string.
A-shape barre at fret 3
What it sounds like
A diminished triad stacks two minor thirds, three semitones each, so its fifth is a diminished fifth, six semitones above the root. That fifth is a tritone, which traditional theory treats as the most unstable interval in tonal music, and it gives the chord its tension. The chord has no perfect fifth, so it does not rest. It leans toward a resolution, and the ear hears its notes as unsettled. The sound is sharp and tense, and the chord usually appears in passing or as a leading-tone chord.
How it is used
In major keys the diminished triad sits on degree 7 as vii°, where the leading tone is the root, and it resolves to I with the root rising a semitone. In minor keys it sits on degree 2 in natural minor as ii°, and on degree 7 in harmonic minor as vii°. The ii° chord often leads to V. Passing diminished chords appear in classical, jazz and pop harmony, moving between two chords whose roots are a step apart.
How it is built
The diminished triad is a root with a minor third and a diminished fifth, 0, 3 and 6 semitones above the root. Common symbols are Cdim, C°, Cm♭5 and Cmin♭5. Built on C, the fifth is G♭, which is the same pitch as F♯, an augmented fourth above C. The inversions are C°/E♭ and C°/G♭. Adding a minor seventh gives Cm7♭5, and adding a diminished seventh gives Cdim7. Each inversion keeps the same three pitches, and only the bass changes.
Which keys contain Cdim
Cdim is a diatonic chord in these keys, where the numeral shows its job:
Scales that fit Cdim
Scales that contain every note of the chord, so they can be played over it:
- C Locrian
- C♯ major
- C♯ harmonic minor
- C♯ melodic minor
- D♭ major
- D♭ harmonic minor
- D♭ melodic minor
- E♭ melodic minor
- E♭ Dorian
- E harmonic minor
- F Phrygian
- F♯ Lydian
- G♭ Lydian
- G harmonic minor
Other C chords
How to practise it
Build a diminished triad on the seventh degree of C major, which is B, D and F, and play it in each inversion. Then play B, D, F and resolve to C, E, G, moving each voice up by step. In G major the chord is F♯, A, C, which resolves to G, B, D in the same way. Listen to the chord's pull toward the tonic each time.
Further reading
- Triads and Inversions: Root Position, Sixth, Six-FourHarmony · 6 min
- Diatonic Chords in Major and Minor Keys ExplainedHarmony · 7 min
Questions
What notes are in a Cdim chord?
Cdim contains C, E♭, G♭. That is the root, third, fifth of the chord.
How do you spell C diminished?
Stack the intervals P1, m3, d5 above C: C, E♭, G♭.
What other symbols mean Cdim?
Lead sheets also write it C°, Co. They are the same chord.
What is the difference between a diminished triad and a minor triad?
A minor triad has a perfect fifth, seven semitones above the root. A diminished triad lowers that fifth by a semitone to six semitones, which creates a tritone with the root. Cm is C, E♭, G. Cdim is C, E♭, G♭. The lowered fifth is what makes the diminished triad sound unstable.
How do you write a diminished chord?
Write it as C°, Cdim or Cm♭5. All three name C, E♭ and G♭. The degree sign and dim are the most common forms in printed music, while Cm♭5 appears in some lead sheets. The seventh version is written C°7 or Cdim7.
Why does the diminished triad sound unresolved?
Its tritone, between the root and the lowered fifth, is the most unstable interval in tonal music, and the chord has no perfect fifth to rest on. The ear expects a consonant triad next, so the chord creates a need that the following chord answers.