The diminished chord is one of the most enigmatic and often misunderstood sounds in music theory. To many people, it sounds quite dissonant and unattractive. However, the diminished chord is a very useful and beautiful harmony when used properly.
The diminished chord is inside of many larger chords and it has interesting intervallic properties that we can study and incorporate into many situations. Read on to learn the secrets of the diminished chord in music theory!
What is a diminished chord
In essence, diminished chords are three note chords composed of two minor third intervals. Remember that a minor third interval is equal to three semitones, or three keys on the piano.
Let’s review a little theory of piano chords. The formula for any major chord is 1 – 3 – 5 (C – E – G). A minor triad has a flat third degree compared to a major chord, so the formula for any minor triad is 1 – ♭3 – 5 (C -E♭ – G).
Diminished chords have a flat fifth degree compared to a minor chord, so the formula for a diminished triad is always 1 – ♭3 – ♭5. The fifth is “diminished” which is where the name diminished chord comes from!
How to make a diminished triad
If we start from middle C and count up a minor third, we find E♭. If we count up another minor third from E♭, we find G♭. This means that a C diminished triad (C dim) is spelled C – E♭ – G♭. Try to play this example on the piano like so:
If we start from the root note D and count up a minor third, we find F. If we count up another minor third from F, we find A♭. This means that a D diminished triad (D dim) is spelled D – F – A♭. Try to play this example on the piano:
How do these triads sound to you? Do they sound more or less stable and resolved than a major triad? What about a minor triad? Do they sound darker or lighter?
More or less dissonant? How can you imagine using these triads in music? What moods or feelings do they create for you?
If we start from the root note E and count up a minor third, we find G. If we count up another minor third from G, we reach B♭. This means that an E diminished triad (E dim) is spelled E – B – B♭. Check out the piano example below:
Try to practice alternation between C diminished, D diminished, and E diminished. Practice them with hands separately and then with hands together. You could even try mixing them up.
Practice a C diminished triad in your left hand paired with an E diminished triad in your right hand. How does that combination sound?
See how many different combinations of diminished triads you can build with both hands. How does the sound of the diminished fifth compare to the natural fifth?
If we start from the root note F and count up a minor third, we reach A♭. A minor third above A♭ is C♭. This means that an F diminished triad (F dim) is spelled F – A♭ – C♭.
You may be wondering why we use C♭ and not B when we spell an F diminished chord. Remember that the formula for any diminished triad is 1 – ♭3 – ♭5. So, when we spell the notes of the chord, we must use the proper scale degrees.
C is the fifth scale degree of F, so we need to spell the chord in terms of C (diminished fifth), even though C♭ and B are technically the same note. If we spelled the F diminished chord F – A♭ – B, that would mean the formula for the diminished chord is 1 – ♭3 – ♯4. This is incorrect as the chord is named for its diminished fifth and not its augmented fourth.
The F diminished chord looks like this example on the piano:
If we start from the root note G and count up a minor third, we reach B♭. Three semitones above B♭ is D♭. This means that a G diminished chord (G dim) is pelled G – B♭ – D♭. Check out the piano example below:
If we start from the root note A and count up a minor third, we reach C. A minor third above C is E♭. This means an A diminished chord (A dim) is spelled A – C – E♭ as in the example below:
Finally, if we begin from B and count up a minor third we reach D and a minor third above D is F. This means a B diminished triad is spelled B – D – F:
Mix and match
Now you have learned all the dim chords starting from natural roots. Nice work! Practice trying to use diminished chords in a
chord progression or improvisation.
How do these diminished chords sound when you mix them together? What does an E diminished chord moving to an A dim chord sound like? What about a B diminished chord moving to a G diminished chord?
Practice mixing and matching these dim chords together until you feel like you have the sound of them in your ears. Try to play these chords while you sing and play piano at the same time.
Diminished chords symbol
The diminished chord symbol is a superscript circle. It looks like this:
Variations on diminished chords
There are two variations on diminished chords: the fully diminished seventh (dim7) chord and the half diminished 7th chord.
Fully diminished seventh chords
To build fully diminished sevent
h chords (dim7), start with the C diminished chord (C – E♭ – G♭) and count up another three semitones until you reach B♭♭. This means the C diminished 7th chord (dim7) is spelled C – E♭ – G♭ – B♭♭.
Yes, B double flat. Remember that the formula for any seventh chord is some variation of 1 – 3 – 5 – 7. So, we must use the note names that correspond to those scale degrees. B is the seventh scale degree of C, so we must use B♭♭, even though it would be simpler to call it A.
You can think of the fully diminished seventh chord (dim7) as a combination of 3 minor 3rd intervals. From C, a minor 3rd above is E♭, another is G♭, another is B♭♭, and finally another returns us back to C.
Interesting music theory
The fully diminished seventh (dim7) forms a circle of minor 3rd intervals and consequently, this diminished chord is symmetrical. We can call any tone in the chord as the root note and the chord will still be a diminished chord.
You could also think of the fully dim seventh as the combination of two diminished 5th intervals a minor 3rd apart or as the combination of two diminished triads. Think C – E♭ – G♭ (C dim) plus E♭ – G♭ – B♭♭ (E♭ dim).
Half diminished 7th
The half diminished chord, also known as the minor seventh flat five chord, is another variation on diminished chords. The half diminished chord is a diminished triad followed by a major seventh.
How to build it
Remember our B diminished chord is spelled B – D – F. If we count up a major third from F, we find A. This means that a B minor seventh flat five chord is spelled B – D – F – A and looks like this on the piano:
Half diminished vs diminished seventh chord
This means that the formula for a half diminished chord is 1 – ♭3 – ♭5 – ♭7. The difference between minor 7th flat 5th and fully diminished 7th chords is the 7th scale degree. In the fully dim chord, there is a fully dim 7th. In the minor 7th flat 5th chord, there is a flat 7th.
You can also think of the minor seventh flat five chord as the combination of a dim chord and a minor chord. Think B – D – F (B dim) plus D – F – A (D minor chord). Cool, right? Dim chords are interesting to play around with in these ways and you can learn more about them with online piano lessons.
Where do diminished chords occur?
These chords naturally occur on the seventh degree of the major scale. Each major scale has a particular progression of chords associated with it. The pattern of chords for every major scale is:
Major, Minor, Minor, Major, Major, Minor, Diminished
Diminished chords in the major scale
The notes of the C major scale are C – D – E – F – G – A – B – C. If we stack triads in the major scale, we come up with the following chords:
C major: C – E – G
D minor: D – F – A
E minor: E – G – B
F major: F – A – C
G major: G – B – D
A minor: A – C – E
B diminished: B – D – F
In a chord progression, we can use these dim chords in the same way we would use a dominant chord. For example, in a piece of popular music in a major key, you might have a chord progression that goes:
C major – A minor – F major – G major
Since this chord progression is in the key of C major, you could play a B dim triad in place of the G major chord. The chord progression would then be:
C major – A minor – F major – B diminished
How does this change the feeling of the song?
You could also introduce diminished chords as leading or passing chords to a related chord. For example, the B dim is spelled B – D – F. You could introduce this chord into progressions in all keys that share any of these tones including D minor and F major.
If you were playing A minor – F major – G major, try introducing the B dim chord before the F major. The dim chord will introduce some tension and then resolve to the major chord. The progression would be A min – B dim – F maj – G maj. Of course, the rhythm with which you are playing these chords will change the nature of the tension and resolution.
Likewise, you could place the dim chord before the dominant chord, G major. Then the progression would be A min – F maj – B dim – G maj. Or you could place it in both settings to really heighten the tension: A min – B dim – F maj – B dim – G maj.
You can use diminished chords into your progressions which will help make your songs more interesting when you learn how to play piano.
The diminished chord is an enigmatic and misunderstood chord in music theory. Learning how to use it in your songs and playing can heighten the emotional depths of your music and make your playing sound more advanced.
You can always learn more about music theory and more advanced chords with Skoove. Check out the interactive lessons on chords, scales, and progressions and dive deeper into music theory today!
Author of this blog post
Eddie Bond is a multi-instrumentalist performer, composer, and music instructor currently based in Seattle, Washington USA. He has performed extensively in the US, Canada, Argentina, and China, released over 40 albums, and has over a decade experience working with music students of all ages and ability levels.