Guitar Music Theory

Learning Guitar Music Theory can be overwhelming, especially if you are just starting out.

There are a lot of things to learn when it comes to music theory – notes, sharps and flats, chords, chord construction, major and minor chords, Chord progressions, barre chords, scales, ….. it’s enough to make your head spin.

The below article demystifies all of this information in a step-by-step, clear, concise way. With easy-to-follow explanations and examples, you will be able to understand all of the above in no time. We urge you to read through to get the full benefit. Let’s get started.

Do guitarists need music theory?

To shine as a future musician or an excellent guitar player, you also need to understand the basics of music theory. Having the dedication to learn music theory from the very start will go a long way in helping you to become a confident and skilled musician and, more importantly, to enjoy what you play!

If you scour the internet, you will get varied opinions on the topic, from not necessary to absolutely necessary. Much of it has to do with the simple reason that it appears to be a very dry subject if you just want to read through unless you start getting the feel of it, and hence, many people want to avoid it.

How deep you want to go with the guitar theory ultimately depends on your aim and your proficiency with your guitar playing. If you just want to casually play some popular music, you don’t require to know much about it, but if you want to make a career in guitar, it will definitely help to know the guitar theory in detail.

As per our years of experience in teaching music, what works best with most of our students is to develop their interest slowly in the guitar theory by introducing different pieces of music and explaining the elements of the theory behind it in short capsules of 10 to 15 min in a total session of about 1 hour. Let us explain some of the benefits in brief here.

  1. Music theory explains things that naturally occur in music – Some of the brightest students with very keen observation power may be able to observe or grasp things and try to experiment with them. But the majority of the students are better off being introduced to the main concepts in a logical sequence by a teacher. This is akin to learning a language. You may be able to learn it by listening or observing to a certain degree. But to reach a higher level, you must have an in-depth understanding of grammar, vocabulary, and other details.
  2. It helps you play by ear – Extending the previous point, while some players are gifted to play by ear, they may not be aware of what element they are playing and why two particular elements are pieced together. Knowing the guitar theory allows you to immediately understand what you are hearing and understand the effect of minor variations on the piece. It gradually develops your ability to play by the ear.
  3. It enhances creativity – Knowing at least the major elements of the music theory will certainly empower you to try the variations and understand their impact, improving your creativity by leaps and bounds.
  4. It helps you to write your own music – A writer is able to write a better article if he has command of his thoughts, has sufficient vocabulary, and is able to articulate. In a similar way, you will develop an ability to write your own music if you have musical thoughts and sufficient knowledge of the musical elements (vocabulary) to articulate.

The Common Terms in Music Theory

Before diving deep into the core concepts of your musical journey, it is a good idea to familiarise yourself with some of the basic terms associated with it.

  1. Sound is the mechanical pressure waves traveling through a physical medium like air, water, etc.
  2. Sound is characterized by many unique properties like amplitude, frequency, speed, duration, etc. But, musicians are mostly interested in frequency, which is measured in hertz, defined as the number of times a pressure wave repeats itself in one second.
  3. Pitch is the specific frequency a vibrating object produces. As an example, the open low E guitar string has a fundamental frequency or a pitch of 82.4 Hz. The pitch can be considered the harmonic value of any note.
  4. A note is just a specific pitch that carries a specific name. Additionally, it is associated with a particular duration, loudness, and quality.
  5. If two sounds of the same note appear different, they are said to have different timbres. For example, two different instruments playing the same note will sound different due to the presence of different overtones. A timbre is also referred to as the sound’s color or quality.
  6. The most confusing term for beginners is “Tone,” which is used interchangeably with many other terms, most commonly with timbre, note, and as a name for a particular musical interval. It is actually a sound with regular note-like properties, except that it constitutes only a single frequency capable of being produced digitally.

Notes in Music

Before learning any language, it is very important to master the alphabet. The same holds true for music. The notes are the alphabet for music. In western music, there are only 12 notes named after the first seven letters of the English language.

It is quite straightforward:


These notes are called natural notes.

Much easier than our full English alphabet, right? So when you learn a new guitar chord, make sure you ask (or learn how to figure it out if you are self-teaching) what the chord notes are and see how they relate to each other.

We should also add that your musical alphabet will repeat over and over again on your instrument. The alphabets are easier to visibly see if you look at a piano keyboard, ask a pianist to show you the musical alphabet, and you will note that it repeats up the keyboard.

The same thing happens on your guitar; however, since we have six strings to work with, the pattern repeats over six lines (strings) instead of one straight line like on the piano (no, that is not to be taken as a temptation to switch to the piano!)

Sharps And Flats

In addition to the seven natural notes discussed above, five notes are lying between them. These are denoted by sharps and flats. A sharp sign means that a note is raised, and a flat sign means that a note is lowered. A sharp is denoted by the symbol “#,” and a flat is denoted by “b

So the twelve notes are A, A#/Bb, B, C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab.

Let’s look at it this way, the note C# is between C and D; the note D# is between D and E. For the flats, we can say that note Bb is between B and A; note Db is between D and C. It is usual to use a sharp symbol when notes are ascending in pitch and a flat symbol when they are descending.

You would have noticed that C# or Db are both between the notes C and D and are harmonically identical, also known as enharmonically equivalent. So, both are exactly the same tones.

Whole Tones & Semitones (Half Steps & Whole Steps)

Also known as half steps and whole steps, whole tones, and semitones are what form music. The distance between any of the 12 notes placed next to each other in the above list is called a semitone or half step. This distance is identical for all the half steps, whether it is between C and C# or between E and F.

If we double this distance, we get a whole tone or a whole step. So, a whole tone is made up of two half tones. For example, the distance between C and D is a whole tone combining two half tones between C and C# with C# and D.

While laying out the definition of a tone, we indicated that the term tone is sometimes used interchangeably with guitar interval. You could have seen this in the explanation of whole and semitones.

BC and EF Exception

It’s all looking quite straightforward right now, right? Sorry, but there is one exception we need to learn about; here it comes.

For reasons we are not yet going to get into, not every natural note in the musical alphabet is separated by a whole tone. Between B and C, the separation is only a semitone, and between E and F, also. If you are feeling a little confused, allow us to outline it clearly for you:

WT = whole tone and ST = semitone

  • A to B = WT,
  • B to C = ST,
  • C to D = WT,
  • D to E = WT,
  • E to F = ST,
  • F to G = WT, and
  • G to A = WT

The Note Circle

You can see the graphical representation of all 12 notes below. This representation is known as the Note Circle.

During the clockwise movement in the circle, the notes are arranged in the order of increasing pitch. Hence we will denote them with a “#” symbol. During anticlockwise movement, they get lower in pitch and are denoted by the “b” symbol.

The Note Circle

What is a Scale in Music?

In simple terms, a scale is defined as an abstract collection of notes and the relationship (known as intervals) between these notes. What is important to understand is that it is just a collection without any sequence or order. Hence, you cannot get any particular melodic arrangement out of it.

It only implies a set of relationships between the notes to define a harmonic space. It is called abstract as no actual arrangement is implied by it. It is not mandatory to play all the notes in a particular guitar scale.

The scales come in many forms. A scale can have 5 notes (pentatonic scales), 7 notes, or even more, but what is common is that all of them have a root note that acts as the center of melody (tonic center) and harmony. All the relationships are defined between this root and the rest of the notes in the scale.

12 notes create 12 harmonic centers of the root notes on which a scale can start. This is true for all kinds of scales, irrespective of the number of notes in them.

Different scales in music have their own scale formula. This formula contains a sequence of tones and semitones that allows you to figure out the notes of any scale and play them.

Scales are used to define & build chords and compose melodies. Chords are used to lay down the harmonic structure of any song. Melodies are played over this harmonic structure. Let us briefly introduce you to different scales and scale patterns.

Different Types of Scales in Music

The most basic scale in the guitar theory is the “Chromatic scale,” also called a master scale.

The Chromatic Scale

The chromatic scale contains all the 12 notes in every octave and thus becomes a super set encompassing all other scales and chords, and so to say, the entire harmonic landscape. However, its practical use is limited to technical exercises for beginners as it is very abstract with very little musical significance.

As stated earlier, all the notes in a chromatic scale are a semitone apart. The human brain does not recognize any musical values in intervals that are equally spaced. To evoke the highest intervals, the intervals should have simple frequency ratios like “3/2,” “4/3,” “5/4,” and so on. If this ratio is whole numbers like 1, 2, 3, 4, etc., like in octaves, it does not interest the brain.

Chromatic scales don’t define any distinct harmonic space or variety. To have that, you need guitar scales with less than 12 notes. Luckily, we have two other scale types to lay the foundation of harmony. They further break up into other types.

Pentatonic scales

The 5 note scales are called pentatonic scales, which means that they have five notes per octave. Five notes can also result in a variety of note patterns, one of which is particularly used by guitarists and defines the minor pentatonic scale and the major pentatonic scale. Pentatonic scales are found in rock and blues music.

They are called major and minor pentatonic because they originate from the 7-note natural minor and major scales, respectively.

Diatonic scales

The seven-note scale patterns have many forms. The most basic form is often called diatonic scales. Any diatonic scale has an even distribution of notes in the octave. They are characterized by 5 whole tones and 2 semi-tone intervals in them. The natural minor and major scales are the diatonic scales. The terms major and minor scales reflect the mood of the scale, with the minor scale on the sad, dark, and thoughtful side, while the major scale sounds happy, bright, and lively like the minor and major chords.

Harmonic and Melodic Minor Scale

In addition to the above, the two other varieties of seven-note minor scales are the harmonic minor scale and the melodic minor scale. These scales are used in classical music, advanced rock, jazz, and nonclassical music.

There are other types of scales – The Blues scale and the Mixolydian Scale. You can read the details in our separate articles.

Relative Scales

Now let us briefly introduce you to the concept of relative major and minor scales. The scale formula for these scales is:

Major Scale: W W H W W W H

Minor Scale: W H W W H W W

The two relative scales have the same notes, chords, and key signatures. Every major scale has a relative minor scale, and vice versa. The relative minor scale of any major scale is the sixth interval of the major scale. Consider the C major scale written down using the above scale formula: C D E F G A B C.

The sixth note in the C major scale is “A,” which implies that “A minor” is the relative minor of the C major. From the formula of the minor scales above, the “A minor” scale is A B C D E F G A.

Let us now find the relative minor of the G major scale. The G major scale is G A B C D E F G, and the 6th note is E, so G major is the relative major of the E minor scale – E F# G A B C D E

Just like you are picking the 6th note to find the relative minor, you can pick the 3rd note on the natural minor scale to find the relative major of a minor scale. See that the 3rd note on E minor scale is G.

What is a Mode in Guitar Music Theory

You have seen above that a pentatonic scale is a collection of five notes oriented around the root. A particular set of intervals applied to the root define the guitar scales.

Consider the “A minor” pentatonic scale ACDEG. It is a collection of notes A, C, D, E, and G. Now, change the root to C, use the same note set, and reorient them to CDEGA, keeping the same sequence. While you have the same five tones, the intervals between them have changed. You have created a different scale – the C major pentatonic scale commonly used in blues, country, rock, pop, etc.

The new scale is also called a mode. You can say that the minor pentatonic scale is a mode of the major pentatonic scale and vice versa. All five notes in the pentatonic scale can act as the root note, each leading to a different mode. Sometimes, the terms scale and mode are used interchangeably.

Modes show the relationships between the scales and the chords.

What is a chord?

When you play a chord, you are playing a combination of notes. Think about it this way; each finger presses down a note, and when several notes are played at the same time, they form a chord. The chords aren’t just for guitar; almost all musical instruments play notes together to make the piece of music, except the single-note instruments.

While a melody is made up of single notes played one after the other to create a tune, a chord is formed by playing several notes at the same time to create harmony.

Guitar chords, like other instruments, come from the notes in guitar scales. Each scale contains a particular set of chords in it that are defined by a root note and a set of intervals relative to it. All these chords coming from a scale are in the same key as the scale.

The name of any chord conveys the kind of notes contained, the root note, and the intervals embedded in its structure. The relation between various notes and the root has often been termed the spelling of the chord.

You can create complex chords by simply naming the intervals in a chord used in very specific situations.

Chord Theory and how Chords are Built

The normal method to construct chords is the interval of thirds. So, all guitar chords have a root note and a series of notes (in the related scale) about the root ascending in thirds.

Like scales, chord theory also has chord formulas to define the chords. As explained to you earlier, chords are formed from the notes in the scale they come from. The chord formula simply shows the scale degrees defining the chord.

As an example, let us G major scale G-A-B-C-D-E-F-G and the chord formula be “1 3 5”. This means the chord consists of the root note, the third and fifth scale degree, which is G (root), B (major 3rd), and D (major 5th). This is the G major chord.

The common variations to the above method of chord construction are:

  • Moving one or more notes up or down.
  • Chord inversion – rearranging the notes.
  • Adding other notes from the scale to existing guitar chords to form the 7th chords, the extended chords (like the 9th chords, the 11th chords, and the 13th chords), the added tone chords, etc.
  • the altered chords formed by replacing one of the notes,
  • Using an interval other than the thirds, known as the non-tertian chords – like suspended chords, etc.

Chord Types

Chords are categorized by the number of notes contained in them. The most common and the 3-note and 4-note chords, but this number can go up in jazz and some classical chords. The common chord types are

  1. Dyads – Chords containing only two notes. Any interval can be used.
  2. Triads – Chords with three distinct notes.
  3. Quadads – Chords with four distinct notes.

Three Fundamental Chord Qualities

Each chord may reflect a different mood, effect, or flavor that characterizes it. These flavors make all guitar chords sound different. Here, the reference is not towards technicalities associated with playing guitar, like pitch, overtones, etc., but the effect these different chord shapes produce.

If you analyze, you will come up with three basic chord qualities that encompass all the chords – major chords, minor chords, and dominant chords.

Major Chord family will usually have a major 3rd or a major 7th. They are happy sounding and provide stability in a major key apart from providing context for melodic direction in any chord changes.

Minor Chord family carries a minor 3rd in it. The chords are sad-sounding and provide stability to a minor key.

The dominant Chord family can be easily recognized by the presence of a major 3rd along with a minor 7th. These chords are quadads, and guitar players use them in all blues music.

Triad Chords

Triads are the most common chords that are simplest and easiest to understand. They usually have two 3rds stacked on top of each other. These thirds are either a major third or a minor third. Different types of triads are as follows:

Major & Minor Triads

A Major triad consists of a root, a major third, and a perfect fifth. This implies that we have a major third above the root and a minor third above the middle note. The chord formula for the major triad is [1 3 5], which makes C major triad {C E G}.

A minor triad is just the inverse of its major cousin – having a minor third stacked over the root followed by a major third. So the chord formula is [1 b3 5], which gives the C minor as {C Eb E}. Please note that a change of just one note (E to Eb), semitone apart, changes the mood of the chord from happy-sounding to sad-sounding.

Augmented and Diminished Triads

The augmented triads have two major thirds stacked on top of each other, which makes them the major triads with a sharp fifth. They contain a root, major third, and augmented fifth (which is the same as the minor sixth) and produce a jarring sound. The chord formula is [1 3 #5], which gives C Augmented chord as {C E G#}

Diminished triads instead have two minor thirds on top of each other. Hence, these are minor triads with flat fifths (tritones) with the chord formula [1 b3 b5], and Cdim would be {C Eb Gb}.

There are many more types of chords like – suspended, quadads, 7th chords, extended chords, added tone chords, altered chords, open chords, barre chords, etc. We will be dealing with these in separate articles.

Chord Progressions.

If you play a series of chords together in a musical way, you are using a chord progression. These are also known as harmonic progression, chord changes, or succession of chords. All popular songs’ structure in western music is built upon chord progressions, so they really are the foundation of harmony.

Chord progressions have a structure or form made up of various parts, as explained below:

  1. One or two chords are at the center of any chord progression, called the “Tonic.” The entire progression revolves around them. They are usually played first.
  2. The next part moves away from the tonic, and the guitarist plays one or more sub-dominant chords.
  3. The third part brings the progression back toward the tonic through the use of dominant chords. Resolution – the most basic unit of the progression – is the movement from a non-tonic chord to a tonic chord. Cadence, on the other hand, is when you use two chords to resolve to the tonic.

The chord progressions are denoted by Roman numerals with dashes in between them. The numerals are in the capital for a dominant or major chord, as against the minor ones.

Some Common Chord Progressions

Let us briefly touch upon the progressions you commonly use when playing real music.

  1. Progression [I – IV – V] – In this chord progression, major IV is the sub-dominant chord, major V is the dominant, and major I is the tonic chord. In the key of C, the progression is C – F – G.
  2. Progression [ii – V – I] – This progression is used in jazz. Minor 2nd is sub-dominant, major 5th is dominant, and major I the tonic. In the key of C, the progression will be D minor – G – C.

You can go through our article on chord progressions to know other commonly used progressions in guitar playing.


If you want to take your guitar playing to the next level, learning music theory is a must. While it may seem daunting at first, with a little effort and practice, you can be on your way to understanding how chords are built, reading and writing music notation, and creating your own songs.

We hope this article has helped give you a basic introduction to music theory for guitar players. We will be introducing you to intervals, the circle of fifths, etc., in a separate article. If you have any questions or want to learn more, please leave us a comment below. And keep practicing – the sky’s the limit!

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