A Guide To Music Intervals: The Gaps Between The Notes

Without intervals we wouldn’t have melody chords, or scales. They really are one of the foundations of music.

In this guide to music intervals, we’re going to cover what intervals are in music as well as all the different ways to categorise them and name them. But first, let’s start with what is an interval?

What is a Music Interval?

An interval in music is defined as a distance in pitch between any two notes.

The larger the interval between two notes, then the greater the difference in pitch between the notes.

And vice versa, the smaller the interval between two notes then the smaller the pitch between the notes.

There are three parts to the way we describe an interval:

  • The distance of the interval
  • The type of interval (the interval quality)
  • Is the interval harmonic or melodic?

Before we talk about those though we’re going to cover the two smallest types of interval: semitones and tones.

Semitones and Tones (Half Steps and Whole Steps)

Semitones and tones or half steps and whole steps, are the building blocks of intervals.

We use different combinations of them to make up all the different types of scales and chords that make music sound so different.

Semitones: The smallest possible interval

The smallest possible interval (in western music anyway) is a semitone, or in the US it’s called a half step. A semitone is the very next higher or lower note.

For example, from E to F or from C to C sharp (C#) on a piano keyboard.

Semitone intervals

What are tones (whole steps)?

The word ‘semi’ means half (it’s the same semi that we get semiquaver from which is ‘half’ of a quaver) so we could think of the word semitone as ‘half a tone’.

A tone or ‘whole step‘, therefore, is an interval of two semitones.

Examples of tones (whole steps)

Names of the Intervals

Now that we know about the two smallest intervals, semitones and tones, we can start looking at some larger intervals and how we describe them.

We describe intervals using numbers depending on how many letter names of the musical alphabet there are between the two notes.

For example, the notes C and D are two letter notes apart and so is an interval of a 2nd.

C – D is a 2nd

But if we look at the notes C and E they are three letter notes apart and so this interval is a 3rd.

C – E is a 3rd

The notes C to F are four letter notes apart and so would be a 4th.

C – F is a 4th

This just carries on, C to G is five letter notes and so would be a 5th.

C to G is a 5th

C to A is six letter notes and so would be a 6th.

C – A is a 6th

C to B is seven letter notes and so would be a 7th.

C – B is a 7th

Lastly, C to the C above it is eight letter notes and so is an interval of an 8th.

C – C is an octave (8ve)

But we don’t tend to call this interval an 8th and instead we call it an octave or 8ve. They both mean the same thing.

The shape octagon has eight sides and the interval octave is eight notes higher.

What is a Unison Interval?

We can also have intervals that are the same note.

For example, two different instruments might play exactly the same note in a piece of music.

Unison intervals

This interval is called a unison.

When we write a harmonic unison interval (more on harmonic and melodic intervals shortly) we write the notes next to each other.

We’ll cover this in the section on harmonic and melodic intervals though.

Interval Quality

Now we’re going to cover the interval quality.

As we don’t just refer to intervals with the number, we also refer to the type of interval.

I’ll explain why we need to distinguish the interval quality with the example below.

Both of these intervals are a third:

Intervals of a 3rd

In the first example, C to Eb is three letter notes: C – D – Eb and so is a 3rd.

And in the second example, C to E natural is also three letter notes: C – D – E and so is a third.

We need to distinguish the type of interval (quality) to differentiate between them both.

What are the Types of Interval Quality?

There are five different types of quality of interval which are:

  • perfect intervals
  • major intervals
  • augmented intervals
  • minor intervals
  • diminished intervals

We’ll go into them now and I’ll explain how to know or work out which of these five types any given interval is.

Before we dive into the first two types of interval, perfect intervals and major intervals, we’re going to look at the major scale.

Every note in a major scale is either a major interval or a perfect interval (starting from the tonic note).

Below are all the intervals in a major scale.

Intervals in a major scale

Perfect Intervals

There are three intervals that are what we call perfect intervals:

  • a perfect 4th
  • a perfect 5th
  • a perfect 8ve (or octave)

To be a perfect interval the upper note has to be in the major scale of the lower note.

If the interval is a 4th, 5th or 8ve and isn’t in the major scale, then it’s not a perfect interval.

For example C to F# is a 4th but is not a perfect 4th as F# is not in C major scale.

Side note: C to F# is actually what we’d call an augmented 4th (or tritone) but more on that shortly.

Below are all the perfect intervals:

Perfect intervals

Next we’ll look at the other intervals in a major scale which are major intervals.

Major Intervals

There are four intervals that are called major intervals:

  • a major 2nd
  • a major 3rd
  • a major 6th
  • a major 7th

So if the upper note of an interval is in the major scale of the lower note (and it’s not a 4th, 5th or 8ve) then it will be a major interval.

When answering questions about intervals you should always work out the number of the interval first by using the lower note as number one and counting how many letter notes there are to the higher note.

Then, if the upper note is in the major scale of the lower note you know that it is going to be either a major interval or a perfect interval.

If it’s a 4th, 5th or an 8ve, then it will be a perfect interval, if it’s another interval then it will be a major interval.

Here’s C major scale with the major intervals marked:

Major intervals

This is the case for every major scale, not just C major.

If the lower note is the tonic and the upper note is in the major scale, it will always either be a major or perfect interval.

Minor Intervals

If we take any of the major intervals we looked at above and make them smaller by one semitone (half step) then they now are minor intervals.

For example, if we took C to E which is a major 3rd and flattened the E to make it an Eb, it now becomes a minor 3rd.

Major 3rd and minor 3rd

Because there are only four major intervals there are also only four minor intervals possible which are:

  • minor 2nds
  • minor 3rds
  • minor 6ths
  • minor 7ths

Here is F major scale but with the 2nd, 3rd, 6ths and 7th notes flattened to become minor intervals.

Minor intervals

So to recap:

  • If the upper note is in the major scale of the lower note it will be either a major or perfect interval
  • If it’s in the major scale and it’s a 4th, 5th or an 8ve then it will be a perfect interval
  • If it’s in the major scale and is a 2nd, 3rd, 6th or 7th then it will be a major interval
  • If it’s a semitone lower than a major interval then it will be a minor interval

Augmented Intervals

An interval becomes augmented when we extend a major or perfect interval by one semitone (half step) without changing the letter name.

So if we took a major second like F to G and made the G a G#, then we’ve made the interval wider by one semitone and so it’s now an augmented 2nd.

Major 2nd and augmented 2nd

It’s the same with perfect intervals, for example, the interval F to C is a perfect 5th but if we make it F to C# (widening the interval) then it’s now an augmented 5th.

Perfect 5th and augmented 5th

So here is F major scale again but with all the notes raised by one semitone and they’re now all augmented intervals.

Augmented intervals

Hopefully, you’re wondering what happens if we flatten a perfect interval by one semitone.

If we do that then we have made the next quality of interval, a diminished interval.

Diminished Intervals

If we flatten any of the three perfect intervals – 4ths, 5ths or 8ves by a semitone, they don’t become minor, they become diminished intervals.

Let’s take the two notes A and D which is a perfect 4th.

If we were to flatten the D to make it a Db it would now become a diminished 4th.

Perfect 4th and diminished 4th

We can also flatten minor intervals by a semitone and they too become diminished.

For example, E to D is a minor 7th, but if we make the D one semitone lower to a Db, it then becomes a diminished 7th.

Minor 7th and diminished 7th

So just remember that:

  • if we flatten a perfect interval by one semitone (half step) it becomes a diminished interval
  • If we flatten a minor interval by a semitone (half step) it becomes a diminished interval
  • If we flatten a major interval by a tone (whole step) it becomes a diminished interval

Music Intervals Chart

To help make sense of all the intervals here’s a chart with the number of semitones (half-steps), the name, the abbreviation and an example of the notes of all the intervals.

Music Intervals Chart
0UnisonPP or P1C – C
1Minor 2ndm2C – Db
2Major 2ndM2C – D
3Augmented 2ndA2C – D#
3Minor 3rdm3C – Eb
4Major 3rdM3C – E
4Diminished 4thD4C – Fb
5Perfect 4thP4C – F
6Augmented 4thA4C – F#
6Diminished 5thD5C – Gb
7Perfect 5thP5C – G
8Augmented 5thA5C – G#
8Minor 6thm6C – Ab
9Major 6thM6C – A
10Minor 7thm7C – Bb
11Major 7thM7C – B
12Perfect 8veP8C – C

Compound Intervals

All the intervals that we’ve looked at up until now have been up to one octave.

These are called simple intervals. But, you can also get intervals that are larger than one octave.

For example C to E the octave above. These types of intervals are called compound intervals.

A simple interval
A compound interval

There are two different ways to name compound intervals which I cover in more depth in my compound intervals guide here.

Harmonic and Melodic Intervals

As well as categorising intervals into their interval numbers: 2nds 3rds 6ths etc, and by the interval quality: major minor perfect etc, we can also categorise intervals into two other groups:

  • Harmonic intervals
  • Melodic intervals

These types of intervals are not to be confused with harmonic and melodic minor scales, those are totally different but we use the same words.

What are Harmonic Intervals?

Harmonic intervals are how we describe two notes that are played, at the same time.

They are played in harmony and so are a harmonic interval.

What are Melodic Intervals?

The opposite of a harmonic interval is a melodic interval which is where the two notes are played one after the other.

They are part of a melody and so are a melodic interval.


That about sums up musical intervals for now.

I’ll be updating this post with some more examples when intervals can get a little bit more complicated with double flats and double sharps and key signatures.

If you’ve got any questions feel free to post a comment below and I’ll do my best to help answer.

Dan Farrant

Dan Farrant

Dan Farrant, the founder of Hello Music Theory, has been teaching music for over 10 years helping thousands of students unlock the joy of music. He graduated from The Royal Academy of Music in 2012 and then launched Hello Music Theory in 2014. Since then he's been working to make music theory easy for over 1 million students in over 80 countries around the world.

21 thoughts on “A Guide To Music Intervals: The Gaps Between The Notes”

  1. Thank you very much for this post. I learn the theory of music, and it is very hard for comprehending the material, and this post helped me very much to comprehend.
    Do you have more material to learn more?
    You made it accessible to me. Thanks a lot for your help.
    I will be happy to get more, and by your way of explaining, I understand
    better. God bless you.

  2. Hi Dan! I found your method easier to understand BUT i have already done my grade 4 & 5 music theory exam (ABRSM) long ago! Truth be told, I can’t get full marks for that section. How I wished you had published this guide earlier 🙁

  3. Hi Lawrence,

    Great to hear and sorry I didn’t publish it sooner 🙁 Glad you passed your exams still though 🙂

  4. Hey Dan. Thanks for the info. Very helpful. How about a situation where the key is D major and and you have the interval between F# to E. Is it a major 7th or a minor 7th?

  5. Hi! This was amazing! Dan I have told you before you have done a great job here! It is a big help to all of us and I fully agree with your approach as well. Thank you so much!!!

  6. Excellent article,

    You write that a major interval reduced by 2 tones is diminished. What about a minor interval raised by 2 tones? Also, where would a diminished octave be used?

  7. Hi Graham,

    Thanks, glad it’s helped!

    You’re almost correct, but a major interval reduced by two semitones (not tones) is diminished. A minor interval raised by two semitones (again not tones) would be an augmented interval.

    But, you can raise and lower intervals by more (for example raising a minor interval by 2 tones) and you then get into doubly diminished and doubly augmented intervals but they’re rare and don’t really have any actual use, just theoretical.

    Hope that helps!

  8. Thank you for the clear explanation! My book doesn’t explain some points and being a self learner with no background in music, I found this site extremely helpful.

  9. Wonderful guide, but i’m confused… how do you flatten a major interval by a tone and make it a diminished interval? I thought only minor and perfect intervals could be diminished. Can you give me an example please?

  10. You’re so close to understanding this. Have a re-read and you should get it. But, let’s say you have a major 3rd, C – E. Flattening it 1 semitone gives us a minor 3rd, flatten that minor 3rd a semitone and you get a diminished 3rd. Two semitones are equal to a tone so we can just skip going to the minor 3rd and go straight to a diminished from the major 3rd by flattening it a tone. Does that make sense?

  11. What a fantastically helpful and well explained article! Thank you so much! One question: what if you’re trying to determine an interval between notes which don’t include the tonic. For example, what is the interval between G and C in the key of D? Is it a perfect 4th because the lower note is a G, or a diminished 4th because the key is D maj?! Thank you.

  12. Great question Tracy. You always workout the interval from the lower note, no matter what key you’re in. G to C is a perfect 4th in Gmajor, D major, B minor or F# major. Hope that makes sense 🙂

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