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The Easiest Way To Understand Chord Extensions

Music Theory Chord Extensions For Guitarist

Have you ever wanted to find out what makes a chord sound special? It’s the change of one or two notes in a chord that give it a specific quality that invokes an emotion. In today’s Music Theory Tips & Tricks, we will be taking a quick look at extensions and using numbers to easily understand the concept. Let’s use the Key of E major.

Understanding the Key of E and applying numbers to them

In the Key of E, E is the root chord which will always be a major. Let us visualize this with numbers and letters:

Notes in E Major: E F# G# A B C# D# Corresponding No.: 1 2 3 4 5 6 7

The reason we use numbers to correspond with the notes is because we write chord extensions such as Eadd2 with the usage of numbers. Instead of saying ‘E Major with a lower octave F#’, we simply say ‘Eadd2’.

How to interpret the numbers in chord extensions

In chord extensions, there are a few common ones that everyone should know, such as m, add, sus and M.

Two ‘m’s? Yes, a small ‘m’ means minor while a capital ‘M’ means major.

EM7 = E Major 7; Em7 = E minor 7.

How then can we apply the numbers to understand the notes in a chord?

E Major 7

To play E Major 7, we need the root (1), major third (3), fifth (5) and major seventh (7) notes in the Key of E.

The root: E; Major Third: G#; Fifth: B; Major Seventh: D#;

When you combine these four notes in a chord with E being the lowest note played, it becomes an E Major 7 chord.

E Minor 7

What about E minor 7? The term ‘minor 7’ refers to flatting the major seventh – D# becomes D.

To play E minor 7, we need the root (1), minor third (G), fifth (B) and minor seventh (D).

The root: E; Minor Third: G; Fifth: B; Minor Seventh: D;

Play these four notes together and you will get a E minor 7 chord.

Understanding Chord Extensions


The term ‘add’ means additional, whereby Eadd2 means ‘E major with an added second note’

To play Eadd2, we need the root (1), major third (3), fifth (5) and second (2);

The root: E; Major Third: G#; Fifth: B; Second: F#;


Lastly, to play Esus, we need the root (1), fourth (A) and fifth (B). The fourth replaces the third which gives it a suspended sound.

The root: E; Fourth: A; Fifth: B;

How many extensions are there in total?

There are many extensions for all chords, here’s a rough list:

add2; add9; add11; add13 5; 7; 6; 13; major7; major9; m7; m9; m11; m13 m7b5; dim; dim7; aug; 7#9; / chords;

There are roughly 20 extensions that are commonly used in music today. Can you imagine learning 20 or more ways to play E? Multiply that by all 12 notes and you will be able to play 240 chords!

What’s next?

Now that you’ve understood what an extension requires, you can apply it to any chord. Can’t figure out how to play C Major 7? If you know your Major scale and what makes up a major seventh chord, you can DIY your way to figuring out how to press it. It greatly improves your memory for that chord instead of just searching it up.

For example,

I know a major seventh chord needs the 1,3,5 and 7 notes in the Key of C.

In C: C D E F G A B

No.: 1 2 3 4 5 6 7

Therefore, C major7 must have at least four notes of C, E, G and B.

Extensions are like formulas which you can apply to any chord. If you see an extension you don’t understand, search the notes it uses and try finding them on your guitar.

If you are interested in learning more about music theory and using colourful chords, consider taking up lessons with us here at Guitar Emerge! Our teachers are able to guide you to both understand and play the guitar well. Sign up for a free trial guitar lesson today.

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