Diminished chord: formula, notes and sound
A diminished chord is two stacked minor thirds (0-3-6 semitones). Hear its tense sound, see it on every root, and learn where it appears in a key.
A diminished chord (diminished triad) is the root, a minor third (3 semitones) and a diminished fifth (6 semitones): two minor thirds stacked. C diminished is C, E flat and G flat; B diminished is B, D and F. It sounds tense and unstable and wants to move on.
Listen to Cdim
C E♭ G♭
What is the formula of a diminished chord?
| Chord tone | Interval from the root | Semitones | In C |
|---|---|---|---|
| Root | root | 0 | C |
| Third | minor third | 3 | E♭ |
| Fifth | diminished fifth | 6 | G♭ |
Formula: 0-3-6 semitones. Written Cdim, C°.
What does a diminished chord sound like?
Tight, dark and restless, like a minor chord that has been squeezed. Its outer notes form a tritone, the source of the tension.
How to recognise it by ear
- Start from a minor chord and lower the top note a semitone: C E♭ G becomes C E♭ G♭.
- In a major key the chord built on the 7th degree is diminished: B D F in C major (vii°).
- If a chord sounds like it cannot be the last chord of a song, think diminished (or dominant seventh).
Quick test: is it a diminished chord?
Four chords on different roots. Each is a diminished chord or a chord it is often confused with.
Score: / 4 (your score updates as you answer)
Diminished chords on all 12 roots
Spelled by letter from the formula, so thirds are always a letter apart (E♭, not D♯, in C minor).
| Chord | Notes | Hear it |
|---|---|---|
| Cdim | C E♭ G♭ | |
| C♯dim | C♯ E G | |
| Ddim | D F A♭ | |
| D♯dim | D♯ F♯ A | |
| Edim | E G B♭ | |
| Fdim | F A♭ C♭ | |
| F♯dim | F♯ A C | |
| Gdim | G B♭ D♭ | |
| G♯dim | G♯ B D | |
| Adim | A C E♭ | |
| A♯dim | A♯ C♯ E | |
| Bdim | B D F |
Frequently asked questions
What notes are in a diminished chord?
Root, minor third and diminished fifth: 1, flat 3, flat 5. B diminished is B D F, C diminished is C E flat G flat, F sharp diminished is F sharp A C.
What is the formula of a diminished chord?
0, 3, 6 semitones: two minor thirds on top of each other.
What is the difference between a diminished chord and a diminished seventh chord?
The diminished seventh adds a fourth note, a diminished seventh (9 semitones) above the root: C E flat G flat B double flat. The plain diminished chord has three notes.
How is a diminished chord written?
Cdim or C° (a small circle). In Roman numerals: vii°.