Musical Intervals: The building blocks of music

COLIN ARCHER

9 min readApr 10, 2021

In this article, you will learn what intervals are and how to name them.

Understanding Intervals increases your understanding of scales, melodic patterns, chord building, chord extensions, and chord progressions.

Introduction to intervals.

Intervals are the difference in pitch between any two notes.

If you play its notes in succession it’s a melodic interval. If you play them together it’s a harmonic interval.

The Pitch of a note is how high or low the note is.

Notes are musical symbols for indicating the location of a pitch.

An interval's size changes as the difference between its notes change. The bigger the difference between its notes the bigger the interval becomes. The smaller the difference between its notes the smaller the interval becomes.

The smallest interval in western music is the semitone. The semitone is also known as a halftone or half-step. The tone is the same as two semitones. The tone is also known as a whole tone or a whole step.

Introduction to the Chromatic scale.

This is a twelve-note scale where each note is a semitone apart. It contains all the 12 notes used in western music. It is also known as the twelve-tone scale.

Below is the C chromatic scale. The top line shows the scale ascending. The bottom line shows the scale descending.

Chromatic notes don’t belong to the scale of the key in use. For example, in the C major scale, the chromatic notes are C#, D#, F#, G#, and A# or Db, Eb, Gb, Ab, and Bb. This is because the C major scale only contains the C, D, E, F, G, A, and B notes.

Below is a list of notes that have the same pitch as each other.

C# = Db
D# = Eb
F# = Gb
G# = Ab
A# = Bb

The 13 intervals of the C chromatic scale.

Below is a list of all the 13 intervals off the chromatic scale in the key of C.

C to C (same note)
C to C#
C to D
C to D#
C to E
C to F
C to F#
C to G
C to G#
C to A
C to A#
C to B
C to C (12 semitones higher)

The properties of an interval.

An interval has two main properties.

Number — The distance between the intervals notes.
Quality — The type of interval.

An interval’s number is the number of inclusive notes between its first and last notes.

Finding the number property of an interval.

The diagram below represents the C major scale. You can use this scale to find the number property for each interval.

To find an interval's number property you count all the notes that the interval contains. This includes the starting and finishing notes but excludes any chromatic notes.

You always count upwards from the scale’s starting note. In the key of C, this will be the C note.

For the C major scale, you would count C, D, E, F, G, A, B, and C, an octave higher. You would not count any of its chromatic notes C#, D#, F#, G#, and A#.

Example: From C to G you would count C, D, E, F, and G which gives you 5 notes.

Counting the notes of the C major scale.

The first interval starts and finishes on a C note with the same pitch. There is only one note to count, the C note. Thus this interval’s number quality is a ‘first’. But this interval has a special name, the ‘unison’ or ‘perfect unison’. Its sometimes noted as the pseudo interval as there is no difference between its 2 pitches.

Counting the interval from C to D gives you 2 notes. These are C and D. Thus this interval’s number quality is a ‘second’.

Counting the interval from C to E gives you 3 notes. These are C, D, and E. Thus this interval's number quality is a ‘third’.

Counting the interval from C to F gives you 4 notes. These are C, D, E, and F. Thus this interval’s number quality is a ‘fourth’.

Counting the interval from C to G gives you 5 notes. These are C, D, E, F, and G. Thus this interval’s number quality is a ‘fifth’.

Counting the interval from C to A gives you 6 notes. These are C, D, E, F, G, and A. Thus this interval’s number quality is a ‘sixth’.

Counting the interval from C to B gives you 7 notes. These are C, D, E, F, G, A, and B. Thus this interval’s number quality is a ‘seventh’.

Counting the last interval from C to C (12 semitones higher) gives you 8 notes. These are C, D, E, F, G, A, B, and C. Thus this interval’s number quality is an ‘eighth’.

But this interval has a special name, the octave. It is the distance from one note to another note with the same name. It can be 12 semitones above or below the original note.

You now have the number properties for all 8 intervals of the C major scale:

Unison (first)
second
third
fourth
fifth
sixth
seventh
Octave (eighth)

The intervals Quality property

You now need the quality property for each interval.

The quality of an interval can either be:

perfect (P)
minor (m)
major (M)
diminished (d, dim or 0)
augmented (A or +)

The letters in brackets are shorthand notations for the quality of each interval.

The Major scales intervals

The major scale only has major (M) and perfect (P) intervals. Its perfect intervals are the unison, the perfect fourth, the perfect fifth, and the octave. Its major intervals are the major second, major third, major sixth, and major seventh.

So you now have the names (and notation) for the following intervals.

perfect unison (P1)
major second (M2)
major third (M3)
perfect fourth (P4)
perfect fifth (P5)
major sixth (M6)
major seventh (M7)
perfect octave (P8)

The notation for an interval combines the qualities symbol with its number.

You now have the 8 intervals of the major scale. This leaves you another 5 intervals to find to obtain 13 intervals of the chromatic scale.

The intervals of the Natural minor scale.

The A natural minor scale contains the same notes as the C major scale but starts from the A note.

The natural minor scale’s unison (P1), perfect fourth (P4), perfect fifth (P5), octave (P8), and major second (M2) are all the same as the major scales. Therefore you only need to count the notes for the third, sixth, and seventh intervals.

As before you only count the notes of the scale (A, B, C, D, E, F, G, and A, an octave higher). You don’t count any of its chromatic notes (A#, C#, D#, F#, and G#).

Once again you count upwards from the scale’s starting note which in this case will be the A note.

Counting the notes of the A natural minor scale

Counting the interval from A to C gives you 3 notes, A, B, and C. Thus this interval’s number quality is also a ‘third’.

Counting the interval from A to F gives you 6 notes, A, B, C, D, E, and F. Thus this interval’s number quality is also a ‘sixth’.

Counting the interval from A to G gives you 7 notes, A, B, C, D, E, F, and G. Thus this interval’s number quality is also a ‘seventh’.

The table below shows the C major scale with the C natural minor scale beneath it. If you compare the third, sixth, and seventh intervals of the natural minor scale against those of the major scale you will notice they are all a semitone lower. Thus they are called minor intervals as they are a smaller version of the major intervals.

You now have the names (and notation) for another 3 intervals.

minor third (m3)
minor sixth (m6)
minor seventh (m7)

It is noted that any major interval can be lowered by a semitone to get a minor interval.

For example, if you take the major third interval C to E and lower it by a semitone to C to Eb you now have a minor third interval.

If you take the major scale's major intervals and lower each one down by a semitone then:

The major second (M2) becomes a minor second (m2).
The major third (M3) becomes a minor third (m3).
The major sixth (M6) becomes a minor sixth (m6).
The major seventh (M7) becomes a minor seventh (m7).

This gives you another name (and notation) for another interval.

The minor second (m2)

You now have 12 of the 13 intervals.

The missing interval doesn’t occur naturally in either the major scale or the natural minor scale when considering the intervals starting from the scale's starting note. (C for the C major scale and A for the A Natural minor scale).

It also has 2 different names depending on whether you lower or raise a note to get it.

If you lower a perfect interval by a semitone it becomes a diminished interval.

The Perfect fifth (P5) lowered by a semitone becomes a Diminished fifth (dim5, d5, or o5).
For example, if you lowered the C major scales G note to the chromatic F# note you would get a diminished fifth interval (dim5, d5, or o5).

Likewise, if you raise a perfect interval by a semitone it becomes an augmented interval.

The perfect fourth (P4) raised by a semitone becomes an augmented fourth (A4 or +4).
For example, if you raised the C major scales F note to the chromatic F# note you would get an augmented fourth interval (A4 or +4)

So the last interval is named either as:

The Diminished fifth (dim5, d5, or o5).
or the Augmented fourth (A4 or +4)

You now have all 13 intervals of the Chromatic scale.

The 13 intervals of the Chromatic Scale.

perfect unison (P1)
minor second (m2)
major second (M2)
minor third (m3)
major third (M3)
perfect fourth (P4)
augmented fourth (A4 or +4) or diminished fifth (dim5, d5, or o5)
perfect fifth (P5)
minor sixth (m6)
major sixth (M6)
minor seventh (m7)
major seventh (M7)
perfect octave (P8)

If you made it too here I’d like to thank you for reading my article. I hope you have got something from it. If you found this useful please let me know. My next article will look at compound intervals and inverted intervals.