Diminished 7 chords
A diminished seventh chord has four notes: the root, minor third, tritone and major sixth. Its formula is 1 b3 b5 bb7. Minor 3rds stacked all the way up: root, minor 3rd, flat 5th and double flat 7th. Its four notes split the octave evenly, so the same shape repeats every three frets.
On C it is written Cdim7, and also C°7 and Co7.
Diminished 7 chords in every key
| Chord | Notes | Shapes |
|---|---|---|
| Cdim7 | C Eb Gb Bbb | guitar · piano |
| C#dim7 | C# E G Bb | guitar · piano |
| Ddim7 | D F Ab Cb | guitar · piano |
| Ebdim7 | Eb Gb Bbb Dbb | guitar · piano |
| Edim7 | E G Bb Db | guitar · piano |
| Fdim7 | F Ab Cb Ebb | guitar · piano |
| F#dim7 | F# A C Eb | guitar · piano |
| Gdim7 | G Bb Db Fb | guitar · piano |
| G#dim7 | G# B D F | guitar · piano |
| Adim7 | A C Eb Gb | guitar · piano |
| Bbdim7 | Bb Db Fb Abb | guitar · piano |
| Bdim7 | B D F Ab | guitar · piano |
Diminished 7 compared
| Chord | Symbol | Formula | Notes | Difference |
|---|---|---|---|---|
| Diminished 7 | Cdim7 | 1 b3 b5 bb7 | C Eb Gb Bbb | |
| Half Diminished | Cm7b5 | 1 b3 b5 b7 | C Eb Gb Bb | Cm7b5 and Cdim7 share C, Eb and Gb. Cm7b5 has Bb, the flat 7th, where Cdim7 has Bbb, the double flat 7th. |
| Diminished | Cdim | 1 b3 b5 | C Eb Gb | Cdim is Cdim7 (C, Eb, Gb and Bbb) without Bbb, the double flat 7th. |
Questions
What is a diminished seventh chord?
A diminished seventh chord has four notes: the root, minor third, tritone and major sixth. Its formula is 1 b3 b5 bb7. Minor 3rds stacked all the way up: root, minor 3rd, flat 5th and double flat 7th. Its four notes split the octave evenly, so the same shape repeats every three frets.
How do you write a diminished seventh chord?
On C it is written Cdim7, and also C°7 and Co7.
What is the difference between Cdim7 and Cm7b5?
Cdim7 and Cm7b5 share C, Eb and Gb. Cdim7 has Bbb, the double flat 7th, where Cm7b5 has Bb, the flat 7th.