Diminished Chords on Piano

How do you play a diminished chord?

The secret to playing a diminished chord is taking a major chord (triad) and lowering the top and middle notes down a half step.

Normal C Major Triad = C E G

C Diminished Triad = C Eb Gb

*Members can click this link for video lessons about diminished chords.

Diminished Chord Theory

To create a diminished chord just play two intervals together: Minor 3rd + Minor 3rd.

C to Eb = Minor 3rd
Eb to Gb = Minor 3rd

so

C to Eb to Gb = Minor 3rd + Minor 3rd

NOTE: Also shown as m3 + m3

You can also look at the intervals going off of the root note:

C to Eb = Minor 3rd (m3)
C to Gb = Diminished 5th (Dim5)

*You’ll notice funky things with diminished chords…like double flats (bb).  Why?  Ok, I’ll tell ya.  Let’s say you are playing a Db diminished chord.  Just think about the letters of the alphabet first.  You need every other letter to create these chords.  So…D…F…A…  And you have to keep those letter (for theory purposes to work out).

We start at Db.  A minor third up is a Fb (I know it’s E…but theory is weird!).  A minor third up from that is Abb (G…but you have to keep the letter name…and that’s the only way to do it).

Confused?  Me too!

When to Use Diminished Chords

When playing a diminished chord by itself, you might wonder when someone would ever want to use them in a progression.  There is no set rule for when they are used, but a common time is when leading to another chord. 

Try playing C (C E G) then C#dim (C# E G) then Dm (D F A).  Notice how the diminished chord leads to the Dm chord?

Half Diminished 7th Chords

To make it a half diminished 7th chord add in a flatted 7th.

Cm7(b5) = C Eb Gb Bb

Minor 3rd + Minor 3rd + Major 3rd

Going off of the root note:

C to Eb = Minor 3rd (m3)
C to Gb = Diminished 5th (Dim5)
C to Bb = Minor 7th (m7)

Fully Diminished 7th Chords

To make it a fully diminished 7th chord add in a diminished 7th.

Cº7 = C Eb Gb Bbb

Minor 3rd + Minor 3rd + Minor 3rd

Going off of the root note:

C to Eb = Minor 3rd (m3)
C to Gb = Diminished 5th (Dim5)
C to Bbb = Diminished 7th (Dim7)

All Diminished Triads

Chord	Root	m3	dim5
Cdim	C	E♭	G♭
C♯dim	C♯	E	G
D♭dim	D♭	F♭ (E)	A (G)
Ddim	D	F	A♭
D♯dim	D♯	F♯	A
E♭dim	E♭	G♭	B (A)
Edim	E	G	B♭
Fdim	F	A♭	C♭ (B)
F♯dim	F♯	A	C
G♭dim	G♭	B (A)	D (C)
Gdim	G	B♭	D♭
G♯dim	G♯	B	D
A♭dim	A♭	C♭ (B)	E (D)
Adim	A	C	E♭
A♯dim	A♯	C♯	E
B♭dim	B♭	D♭	F♭ (E)
Bdim	B	D	F

Fun Fact

When you play a fully diminished chord you are actually playing 4 chords at once.  Because of the way the internals line up, for example, in a Cº7 chord (C Eb Gb Bbb) you are playing all of those diminished chords at once (just inverted).  Cº7, Ebº7, Gbº7, and Bbb or Aº7.

Cool right!!???

All Diminished 7th Chords

Chord	Root	m3	dim5	dim7
Cdim7	C	E♭	G♭	B (A)
C♯dim7	C♯	E	G	B♭
D♭dim7	D♭	F♭ (E)	A (G)	C (B♭)
Ddim7	D	F	A♭	C♭ (B)
D♯dim7	D♯	F♯	A	C
E♭dim7	E♭	G♭	B (A)	D (C)
Edim7	E	G	B♭	D♭
Fdim7	F	A♭	C♭ (B)	E (D)
F♯dim7	F♯	A	C	E♭
G♭dim7	G♭	B (A)	D (C)	F (E♭)
Gdim7	G	B♭	D♭	F♭ (E)
G♯dim7	G♯	B	D	F
A♭dim7	A♭	C♭ (B)	E (D)	G (F)
Adim7	A	C	E♭	G♭
A♯dim7	A♯	C♯	E	G
B♭dim7	B♭	D♭	F♭ (E)	A (G)
Bdim7	B	D	F	A♭