Understanding Guitar Scales: Guitar Scales Explained


Guitar Scales Explained

Scales are any set of notes ordered by pitch and are the building blocks for melody and harmony, in particular chords. The major scale is the most fundamental and is used in comparison to define all other scales. Understanding step patterns and scale formulas is key to understanding scales and their role in music. Guitarists are advised to learn the major and minor scale, pentatonic major and pentatonic minor scale along with the blues scale.

What are scales?

Ever wondered what scales are and why they are important for guitarists? In the following article we’re going to answer some of the most common questions around the topic of guitar scales including:

  • What scales are
  • Why they are important for guitarists
  • The different types of scales
  • Step patterns and formulas
  • How to read scale patterns and diagrams
  • Which scales guitarists should learn

This article is the second of a series on basic music theory for guitarists. If you haven’t read the first article on ‘How to learn all notes on guitar’, while not strictly necessary, may help clarify some of the points raised.

So what are scales exactly?

Scales are any set of notes ordered by pitch.

Scales are a fundamental aspect of music theory, and while music theory can appear complicated, scales simply consist of any set of notes, provided they are arranged in order of pitch e.g. from low to high (ascending scale) or high to low (descending scale), generally within a given octave and then repeating the same pattern across octaves.

Another way of interpreting scales would be to consider them as defining how an octave can be divided into steps.


Why Learn Scales?

There’s two reasons guitarists should understand and practice scales.

Firstly, there’s music theory.

If you are learning guitar scales and understand guitar scale theory e.g. how specific notes relate to one another and how this relates to chords you will have a better understanding of music.

This is useful when it comes to improvisation, developing your ear e.g. recognising notes and intervals (the distance between notes), songwriting, and communicating with other musicians.

Secondly, practicing scales is useful for building muscle memory and dexterity and over time will be the backbone of developing good single note technique and ultimately speed for the lead guitar player when playing a guitar solo for example.


That’s the Tonic

The first note of a scale is known as the tonic and this defines the key (also referred to as the ‘key’ note). For example if you play the major scale, starting on the B as per the example below:

B Major Scale
B – C# – D# – E – F# – G# – A#

You would be playing the B major scale. If you started a half step up on the C you would be playing the C major scale, or if you followed a different pattern you would still be playing a type of C scale as it is defined by the tonic.

 If you are unfamiliar with half and whole tones click here to learn more
C Major Scale
C – D – E – F – G – A – B

The tonic, often referred to as the root note (technically the two terms indicate different things) or starting note defines the key. So, if your tonic is the 1st fret of the 6th string and you followed the pattern above you would be playing the F major scale, if you started on the 3rd fret it may be the G major scale depending on the notes you play next.

It can be useful to think of the tonic as the note the other notes revolve around. Our ears have an expectation that a melody will resolve e.g. keeps coming back to the tonic. This build up of tension and release is a key element of writing music.

What’s the difference between the Tonic and Root Note?
Tonic refers to melody, root refers to chords.

They are often the same but the two terms mean different things. For instance the tonic is the note a scale, or melody or section of a melody begins and resolves on. Some people refer to this as the ‘home note’ and our ears come to expect the melody to resolve on this note or keep coming back to this note.

The root is simply the root note of a chord e.g. This is often the first scale degree, or first note of the corresponding major scale. The root note however, isn’t always the first note of a chord, as chords are often inverted meaning the third or fifth degree is the lowest note. Otherwise the terms ‘root note’ and ‘tonic’ could be used interchangeably.


Types of Scales

The Chromatic Scale

Western music consists of 12 notes:

The Chromatic Scale

When these 12 notes are divided (in much the same way the scale length of your neck is divided up by frets) and assembled in order of pitch they form the chromatic scale, also referred to as the 12 tone scale. The chromatic scale is the ‘master scale’ that all other scales are built from and each note is separated by a half tone e.g. A – A# is a half tone, as is B – C.

Because the chromatic scale includes every available note in the western music system it’s rarely used in a practical sense. This is because by not leaving out any notes it lacks structure or definition, and it is often the notes we leave out that define the music we are playing.

A better way to look at the chromatic scale is that it can be used to build other scales, with this in mind it can be useful to consider the chromatic scale as the ‘musical alphabet’.

In the spoken and written word, we extract letters from the alphabet to form words and sentences to communicate ideas. In music, the ‘musical alphabet’ is the chromatic scale, and notes can be extracted from it which can then be used to create musical ideas in the form of melody (single notes) or harmony (chords).
Chromatic Scale to Major Scale to Major Chord

There are many different types of scales, and within each category, different subcategories exist. We can break them into the following based on the notes included:

Scale name Notes per octave
Chromatic 12
Octatonic 8
Heptatonic 7
Hexatonic 6
Pentatonic 5
Tetratonic 4
Tritonic 3
Ditonic (Ditonic (not to be confused with a Diatonic scale – a scale consisting of 5 natural notes and two accidentals e.g. sharps or flats) 2
Monotonic 1

Most of the scales relevant to guitarists consist of between 5 (Pentatonic) and 7 (Heptatonic). For example, both the major and minor scales are heptonic, while the pentatonic major and minor consist of 5 notes. 8 (Octonic) note scales are also used, however mostly in jazz.


Diatonic Scales

Diatonic scales (not to be confused with ditonic) refer to the construction of a specific type of scale rather the amount of notes included within it.
For example, diatonic scales are constructed from 7 notes (heptonic) that contain 5 whole notes and 2 half notes, with the two half notes being separated by 2-3 whole steps. Major scales are diatonic scales, as they contain 5 whole notes, 2 half notes and the 2 half notes are separated by 2 whole steps.
If we look at the C major scale, we see this in action:

C Major Scale

Root Whole Step Whole Step  Half Step Whole Step Whole Step Whole Step Half Step
C D E F G A B C

Keep in mind, the C major scale doesn’t include accidentals (sharps or flats) and the final C is a repeat of the root note, meaning while there are 8 notes written above, the scale only contains 7 notes from start to finish.


Step Patterns and Formulas

We can construct and understand how scales are constructed in one of two ways, either by the step pattern or by the scale formula.

Step Patterns

Step patterns refer to the order of whole and half steps in a given scale, written as ‘W’ for whole step and ‘H’ for half step. As guitarists we can think of steps as frets e.g. a half step is equal to 1 fret, a whole step is equal to 2 frets.

Major scale step pattern
W – W – H – W – W – W – H

For instance the A major scale consists of the following steps (repeating on the A an octave higher):

The Major Scale - Whole and Half Steps

Using the table below and the scale patterns for the major scale (W-W-H-W-W-W-H) we can construct major scales in all keys, as the pattern remains the same, the difference in notes included in each scale is defined by the tonic or starting note.

Root Whole Step Whole Step Half Step Whole Step Whole Step Whole Step Half Step
A Major Scale A B C♯ D E F♯ G♯ A
B Major Scale B C♯ D♯ E F♯ G♯ A♯ B
C Major Scale C D E F G A B C
D Major Scale D E F♯ G A B C♯ D
E Major Scale E F♯ G♯ A B C♯ D♯ E
F Major Scale F G A Bb C D E F
G Major Scale G A B C D E F♯ G
Why do some scales use sharps, while others use flats or a mix of both?
While technically using either would be understood, in diatonic scales notes are not repeated e.g. we do not use A and A# or Bb and B. Take the F Major scale example above, we could have used an A♯ instead of Bb, but by using the Bb all seven letters are represented in the scale.

Scale Formulas and Intervals

Scale formulas use numbers to compare to specific notes of the major scale. This is why it is such an important scale. Scale formulas allow us to use the major scale as a parent scale, or reference for all other scales and modes. To put it simply, these formulas tell us which notes are the same and different to the notes of the major scale.

For example, the formula for the major scale is: 1 , 2 , 3 , 4 , 5 , 6 , 7 . The individual numbers are referred to as scale degrees. Intervals are based on these degrees, starting from the first note. For example the interval between the first two notes is a major second , while the interval between the first three notes is a major third.

We’ll use the C major scale as an example again, as it contains all natural notes e.g. no sharps or flats:

Scale Degrees 1 2 3 4 5 6 7
Scale Notes C D E F G A B
Intervals Unison Major 2nd Major 3rd Perfect 4th Perfect 5th Major 6th Major 7th

As you can see the scale degrees align with the intervals.

For example the 2nd note is a major second while the third is a major third. By changing the intervals we change the scale. For example if we flatten the 3rd note of the C major scale above to D# it becomes a minor third. This does not apply to perfect 4ths and 5ths, which are neither major nor minor by nature. When raised a half step they are ‘augmented‘ and ‘diminished‘ if lowered a half step.

Intervals are useful, up to a point. While there is more that could be dicussed it’s useful to remember that the scale degrees of the major scale align with the major intervals and the scale degrees of the minor scale align with the scale degrees of the minor scale, for example:

The scale formula for the minor scale is: 1, 2, ♭3, 4, 5, 6, ♭7

This basically means we use the first and second note of the major scale, while the third note is flattened by a half tone (equal to 1 fret on the guitar fretboard) and means the major third is flattened and is now a minor third. We then use the 4th and 5th notes without changing them, and flatten the 6th and 7th a half step, making the major 6th a minor 6th and the major 7th a minor 7th.

Knowing what we now know about scale formulas, in simple terms this means we can build a minor scale from a major by flattening the 3rd, 6th and 7th notes, as per the example below.

Major Scale  1 2 3 4 5 6 7
Minor Scale Formula 1 2 ♭3 4 5 6 ♭7
Major Scale Notes C D E F G A B
Minor Scale Notes C D ♭E F G ♭A ♭B

I have listed the scale formulas for the minor, minor pentatonic, and blues scale below which tend to be the most utilized by guitarists depending on genre.

Major Scale 1 2 3 4 5 6 7
Minor Scale 1 2 ♭3 4 5 6 ♭7
Major Pentatonic 1 2 3 5 6
Minor Pentatonic 1 ♭3 4 5 ♭7
Blues Scale 1 ♭3 4 ♭5 5 ♭7
 * Remember this type of scale (pentatonic) only contains 5 notes compared to 7 for the major and minor scale. 
Why do you see flats and sharps written before and after natural note names?
When composing music the accidental (the sharp or flat note) is written before the note. When simply written down or spoken we say the name of the note first followed by the sharp or flat.
Why does the C major scale contain no sharps or flats?
As we know from discussing step patterns, the major scale consists of the following step patterns and corresponding notes as shown below in the table. As it happens, using the step pattern for the major scales beginning on C results in no accidentals being included in the scale.

W W H W W W H
C D E F G A B

Scale Patterns

You have probably seen a scale diagram before. They are similar to chord diagrams and simple to understand once you know how they are laid out.

In the diagram below the scale diagram is shown in horizontal format and like most scale diagrams covers two octaves. You will also see scale diagrams in vertical format at times, however the same rules still apply.

G Major Scale

Scale Patterns - Explanation

 

Firstly, scale diagrams contain 6 horizontal lines with each line representing a guitar string, with the bass notes on the bottom and treble notes at the top. In the case of a vertical scale diagram the low E will be displayed as the line furthest to the left.

The lines running vertically represent the frets, again this will be shown horizontally if in vertical format.

The dots represent the notes that make up the scale. In the example above the white dots show the tonic, in this case G.

Some scale patterns also include numbers representing fingers as the suggested finger to use to play the specific note. Keep in mind, there are as many ways to play scales as there are chords, depending if you prefer to stay within a fixed position (caged system) or want to play higher up the neck (3 notes per string method) or another pattern containing the notes of the scale.


The Caged System

The caged system takes its name from the fact that it utilises 5 open major chord shapes: C , A , G , E and D which can then be moved up or down the neck to create different chords, provided the index finger is positioned where the nut would otherwise be if you were playing within the first four frets.

The caged system is a way of visualising chords and scale shape relative to the fretboard using set patterns contained within a 4 fret position (occasionally 5) that can be moved up or down the neck changing the chord or tonic being played. If you incorporate barre chords into your playing, you are already using the CAGED system when playing a chord progression, the mnost common being the A and E shape.

For example, if you play an open A shape on the 4th fret while barring the 2nd fret with your index finger you are playing a B chord. An E chord shape on the 5th fret with the 3rd fret barred would therefore be a G.

The CAGED system is useful because it can help unlock the guitar neck, and allows you to do a great deal with basic moveable shapes.

I’ll cover the CAGED system in a future article but for the purpose of understanding how it relates to scales, it’s important to know the scale patterns utilised fit closely to the corresponding chord shapes, making it simpler to visualise how these relate to each other. This also makes it easier to play extended chords e.g. adding a 9th scale degree for example.

The patterns will also be contained within 4 frets, with one finger assigned to each fret. Each pattern can be moved, which changes the key.

For instance, the diagram we used earlier for the G major scale can be transposed to A by simply by moving the entire pattern a whole step (2 frets) higher up the neck.

A Major Scale – Caged System

Guitar Scales Explained

We’ll be using the CAGED system to demonstrate scale patterns for most of the remainder of this article as it makes a good starting point for beginners new to music theory, but other patterns including the ‘three notes per string‘ method are also widely used.


Three Notes per String

As the name implies, this system incorporates three notes per string. Its main benefit is it allows the guitarist to extend past just the two octaves the CAGED system allows for.

G Major Scale – 3 Notes per string

G Major Scale - Three Notes per String

It’s up to you which method you use. For those new to guitar I’d recommend the CAGED system as this will make the most sense visually in how it relates to chords.

The three note per string system is arguably better for more advanced players who want to utilise the length of the neck in their lead playing and their fingers are more adjusted to the longer stretches required.


Which scales guitarists should learn?

There are 6 scales every guitarist should learn to begin with, these are:

  • The Major Scale
  • The Natural Minor Scale
  • The Minor Harmonic Scale
  • The Major Pentatonic Scale
  • The Minor Pentatonic Scale
  • The Blues Scale

I’ve provided scale diagrams for each below, along with TAB. For the sake of consistency I’ve listed all scales in the key of G but all patterns used are movable as the tonic of the scale is always the first note shown.


The Major Scale

If you are interested in music theory in any capacity, the major scale is the first scale you should learn as it is the most important in music, aside from the chromatic scale. It consists of 7 notes (heptonic) in total and uses the following note intervals:

Major scale step pattern
W – W – H – W – W – W – H

If you recall the section on ‘step patterns’ this should begin to make sense, and you may also recognise the major scale as diatonic. Remember, regardless of where you shift the pattern the intervals between notes remain the same.

G Major Scale Pattern (caged position)

G Major Scale Pattern - Caged

G Major Scale Tab (caged position)

G Major Scale - Tab


The Natural Minor Scale

The natural minor scale is often referred to as simply the ‘minor scale’ or ‘aeolian mode’ (we’ll cover modes in a future article). Understanding the minor scale will allow will help you build other minor scales including the harmonic minor scale and the melodic minor scale which only differ slightly.

The minor scale also contains 7 notes (heptatonic) but differs in the fact that the 3rd, 6th and 7th steps are flattened by one semitone or fret.

Natural minor scale step pattern
W – H – W – W – H – W – W

G Natural Minor Scale Pattern (caged position)

G Natural Minor Scale Pattern (Caged Position)

G Natural Minor Scale Tab (caged position)

G Natural Minor Scale - Tab - Caged Position


The Harmonic Minor Scale

The harmonic minor scale, also known as Aeolian ♯7 is exactly the same as the natural minor scale except the last scale degree is raised by a half tone, as indicated by the 1 1/2.

Harmonic minor scale step pattern
W – H – W – W – H – 1 ½ – H

G Harmonic Minor Scale Pattern (caged position)

G Harmonic Minor Scale Pattern - Caged Position

G Harmonic Minor Scale Tab (caged position)

G Harmonic Minor Scale Tab - Caged Position


The Major Pentatonic Scale

Unlike the major and minor scales which contain 7 notes, Pentatonics use 5 notes. We already know ‘tonic ‘ refers to the key note. Penta in Greek means 5, hence Penta + tonic refers to a ‘5 note scale’.

Penta (5) + Tonic (note) = 5 note scale

The difference between the major and major pentatonic is the removal of the 4th and 7th notes.They are synonymous with rock and country and would have to be the most played of all.

Removing the two notes (4th and 7th) removes the half steps and as a result more dissonant (disharmonious) intervals.

Major pentatonic scale step pattern
W – W – W + H – W – W + H

G Major Pentatonic Scale Pattern (caged position)

G Major Pentatonic Scale Pattern - Caged Position

G Major Pentatonic Scale Pattern (caged position)

G Major Pentatonic Scale Tab - Caged Position


The Minor Pentatonic Scale

Just as the major pentatonic contains 5 notes from the major scale, the minor pentatonic contains 5 notes from the minor scale, leaving out the 2nd and 6th notes respectively. The minor pentatonic can be heard throughout rock and blues and for most guitarists is the most common scale they will use.

Minor pentatonic scale step pattern
W – W – H – W – W – W – H

G Minor Pentatonic Scale Pattern (caged position)

G Minor Pentatonic Scale Pattern - Caged Position

G Minor Pentatonic Scale Tab (caged position)

G Minor Pentatonic Scale Tab (Caged Position)


The Blues Scale

The blues scale utilises 6 notes (hexatonic) and is almost identical to the minor pentatonic, with the addition of the ‘blue note’ or diminished 5th. (Added in blue below) As the name implies it works particularly well over a 12 bar blues chord progression.

Blues scale step pattern
W + H – W – H – H – W + H – W

G Blues Scale Pattern (caged position)

G Blues Scale Pattern - Caged Position

G Blues Scale Tab (caged position)

G Blues Scale Tab - Caged Position


Summary

I hope the information above helps explain exactly what scales are and why they are so important for guitarists for both gaining an understanding of the fretboard along with building finger dexterity through practice.

We’ll cover the topic of scales in more detail in coming articles including, the use of alternate picking and some of the different scale patterns available and modes and how they relate to scales.

In the meantime if you have a question or something to add why not leave a comment below and join the conversation.

Marty

My names Marty, I've been into guitars for over 30 years. Theacousticguitarist.com is my blog where I write about acoustic guitars, music, and home recording.

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