How to work out diminished and augmented intervals!

By Jade Bultitude
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Before reading through this blog post, make sure you are happy working out the intervals number (distance between the two notes) and working out whether it is a major, minor or perfect interval! Today we will be taking this idea a little further by talking about diminished and augmented intervals!

If you remember, in order to work out our interval we have to ask ourselves ‘is the top note in the scale of the bottom note?’

But let’s get more specific, we always have to base this question on the major scale. So let’s rephrase that question…

‘Is the top note in the major scale of the bottom note?’

Let’s practice a few examples to refresh our memories!

What interval do we have below?

That’s correct – this is a major 6th. This is because E natural IS in the G major scale!

What about this one?

That’s correct this is a minor 3rd. This is because Ab is NOT in the F major scale. We have an A natural in F major, Ab is ONE semitone below A natural, bringing us to the minor. 

Take a look at the piano below to clearly see the semitone. 

Last revision example…

That’s correct this is a Perfect 5th! Remember 4th, 5th and 8ve are the same in both the major and minor scales and therefore cannot be labelled as major or minor… we simply use the word perfect! 

Now let’s take these intervals a little further…

On top of the descriptions Major, Minor and Perfect, we also have the descriptive words Diminished and Augmented

Have a look at the diagram below:

We have two separate diagrams, one for the major/minor intervals (2nd, 3rd, 6th and 7th) and one for the perfect intervals (4th, 5th and 8ve). 

Both categories can have augmented or diminished intervals! 

Augmented intervals

An augmented interval is ONE semitone larger than a major or perfect interval. 

Let’s have a look at the below interval:

As you can see we have an F natural to A double sharp. 

Is A double sharp in F major? No it is not… In F major we have an A natural. 

Take a look at the piano below… How many semitones have you gone up to reach A double sharp?

We have gone up two semitones. This makes this interval an Augmented 3rd!

Let’s try one more!

We have an F sharp followed by a C double sharp. 

Is C double sharp in F sharp major? No it is not… In F sharp major we have a C sharp. 

Take a look at the piano below… How many semitones have you moved? 

We have gone up one semitone C sharp-C double sharp. This makes this interval an augmented 5th!

Diminished intervals

A diminished interval is ONE semitone smaller than a minor or perfect interval. 

Let’s have a look at the below interval:

As you can see here we have a G natural to E double flat. 

Is E double flat in G major? No it is not… In G major we have an E natural. 

Take a look at the piano below… How many semitones have you gone down to reach E double flat?

We have gone down two semitones. This makes this interval a diminished 6th

Let’s try another one

Here we have a G natural to C flat. 

Is C flat in G major? No it is not… In G major we have a C natural. 

Take a look at the piano below… How many semitones have you gone down to reach C flat?

That’s correct, we have gone down one semitone! Now, this is where we can get confused, the interval G-C is a 4th. Remember a 4th is not major/minor, it is perfect! This means we only need to go down one semitone in order to reach… diminished 4th!

I hope that has helped your understanding of augmented and diminished intervals – to practice further, download the practice worksheet! 

Next week we will look at what if we have a note at the bottom that we don’t know the scale for, do you know? 

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AUTHOR
Jade is an experienced musician and teacher as well as being the founder of Music Theory Foundations. She has been helping people learn music theory for more than 10 years from pre school children all the way to degree level studies.