In this lesson you will learn about what intervals are, how to find them, and begin to understand how they relate to all music theory concepts. If you want a thorough understanding of every music theory concept, then you MUST understand intervals properly and thoroughly.

What Are Intervals?

Intervals are the building blocks of music. They are a way of measuring the distance and relationship between pitches, whether they are played simultaneously as a chord, or vertically as a melody.

The function of notes and intervals is very different. While notes tell us the absolute position of a pitch on our instrument, intervals are relative to a starting pitch, root note, or key.

The Numbering System

The first thing that you should know is that there are, in total, 7 “natural” intervals in twelve-tone western music. Quite simply these are referred to as 1, 2, 3, 4, 5, 6, 7. There are also 5 interval qualities which you need to know which are; Major, Minor, Perfect, Augmented, and Diminished. We’ll expand on what these qualities mean shortly.

One thing that I want to highlight at this point before we go any further is that you must not confuse the terms “natural, sharp, or flat” with the alphabetical note names. We are strictly referring to intervals at this point and not their alphabetical values.

Below is the pattern we will be using in this lesson which contains all 7 natural intervals. You may already recognise this pattern, it’s quite simply the major scale. In this instance we are playing an A major scale because the root, or first note of the scale, is an A note. The root note is the reference for all of the other intervals within the scale.

The first picture demonstrates both the frets, and some of the note qualities that I mentioned earlier. R = Root interval, M = Major interval, and P = Perfect interval. Notice that all natural intervals are either perfect or major. The second picture demonstrates the formula of this scale in whole and half steps.

We can label the intervals shown above as follows:

• First degree: 1, or Root
• Second Degree: 2, or Major 2nd
• Third Degree: 3, or Major 3rd
• Fourth Degree: 4, or Perfect 4th
• Fifth Degree: 5, or Perfect 5th
• Sixth Degree: 6, or Major 6th
• Seventh Degree: 7, or Major 7th

Let’s now introduce you to the sharps (#) and flats (♭) in-between these 7 natural intervals. The first thing that we can try is to flatten (-1 semitone) all of our major intervals.

By changing the order of the intervals we are changing the name of the scale, but don’t worry too much about that now – we’ll explore individual scales in their own lessons. In the above picture you will notice the previously capitalised M’s are now lower case. M = Major, m = minor.

We’ve discovered all of our possible major, minor, and perfect intervals, but there are two remaining which we haven’t seen just yet. Let’s revert back to our natural position and try to experiment with our perfect intervals. In this natural major scale pattern we are not able to flatten our 4th degree since the major third belongs there, so let’s sharpen it instead.

This is what’s called an augmented 4th. Augmented intervals are one semitone above a perfect or major interval.  A = Augmented

Incidentally the♭5 interval, also known as the diminished 5th, occupies the same position as an augmented 4th! Diminished intervals are one semitone below a perfect or minor interval. d = Diminished.

So how do we know whether to call it a diminished 5th or an augmented 4th? Well, if there’s already a 4 in the scale, we must use a ♭5. Similarly if there’s already a 5 in the scale we would use a #4.

Summary

Below is a chart listing all possible interval names and qualities. Make sure that you thoroughly understand this numbering system if you want to speed up your understanding of music theory. It is important that you are eventually able to find intervals at ease, in any key or position of the neck.

Interval	Quality	Short	Distance
1	Perfect Unison	P1	–
♭2	Minor Second	m2	H
2	Major Second	M2	W
♯2 /♭3	Augmented Second / Minor Third	A2 / m3	W  H
3	Major Third	M3	W  W
4	Perfect Fourth	P4	W  W  H
♯4 /♭5	Augmented Fourth / Diminished Fifth	A4 / d5	W  W  W
5	Perfect Fifth	P5	W  W  W  H
♯5 /♭6	Augmented Fifth / Minor Sixth	A5 / m6	W  W  W  W
6	Major Sixth	M6	W  W  W  W  H
♭7	Minor Seventh	m7	W  W  W  W  W
7	Major Seventh	M7	W  W  W  W  W  H

Luckily for guitar players, once you’ve learned something in one key, you can simply move the patterns and shapes to any other key and the position of the intervals will always remain the same. In this lesson we referenced everything to the key of A. If for example you wanted to try the same thing in C, you would just move the exact same shapes and patterns up to the C note.