Guitar Chord Theory

How To know Which Chords Go Together

Chord Chart with Guitar Pick Sitting on top

In the following article, we’re going to dabble in some basic guitar chord theory, analyze common chord progressions, and explain the relationship between chords, and how to establish which chords work well together. So, if you are currently using trial and error to find chords to add to your song ideas, stay tuned! This should really help.

All music has a key, and all keys have a corresponding scale. The notes included in the major scale, for example, are the same as the root notes of the chords within that key. Determining the ‘quality of each chord’ e.g. major, minor, diminished, etc. depends on the chord scale. For example, major keys are ordered in the following way: major, minor, minor, major, major, minor, and diminished.

While the explanation above will help you determine the chords within a specific key, allowing you to play chords that are ‘in key’ there’s plenty more to understanding how and why specific chords work well together.

And, while many guitarists might be turned off by music theory in favor of ‘feel’. The two can exist in, dare I say it, perfect harmony.

Chords that go together: keys and chords

When trying to work out chords that go together, there are two main areas to address.

First, what are the letter names of the chords, or root notes of the chords within a given key, and secondly what is the quality of the chords? Quality refers to whether the chord is major, minor, diminished, or augmented.

Note Letter Names

Working out the letter names of chords within a given key is fairly straightforward.

As we discussed in the introduction, the notes in the major scale represent the root notes of the chords within a major key.

All major scales are derived from the chromatic scale, the 12 available notes used in Western music:

The Chromatic Scale


These 12 notes are known as the chromatic scale and all major scales take 7 notes from this set of 12 notes in the following sequence:

Whole Step (Whole Tone)Whole Step (Whole Tone)Half Step (Semitone)Whole Step (Whole Tone)Whole Step (Whole Tone)Whole Step (Whole Tone)Half Step (Semitone)
  • Continuing the sequence results in the next being a half step or semitone, which would land us on the tonic note again.

The key of the scale taken is determined by the tonic chord, which is built from the first note in the scale, and the formula starts on the tonic.

The E major scale, for example, would then look like the example below, as the tonic or first note of the scale is E and the notes included in the scale follow the sequence above (whole, whole, half, whole, whole, whole).

Each note of the major scale has a number, which we call a scale degree, as shown in the table below:

E Major Scale

Scale Degrees1234567

The D major scale, for example, would use the notes and scale degrees used in the table below.

D Major Scale

Scale Degrees1234567

Once we understand scales and scale degree formulas we can begin to build other scales e.g. the minor scale, and the blues scale to name just two, and subsequently chords.

Chord Qualities


There are three main types of chords.

When most people refer to chord types they are thinking in terms of minor, major, suspended, augmented, etc. But this is actually the chord’s ‘quality’.

Chord type refers to how the chord is built.

There are 3 ‘types of chords. Triads, 7th chords, and extended chords. A basic triad is a three-note chord built by stacking thirds, 7th chords are chords that contain an additional 7th e.g. a C7 chord is built on a major triad with a minor 7th interval added and extended chords are chords that utilize additional intervals beyond the 7th.

We will deal mostly with triads in this article, but if interested you can read more about 7th and extended chords here.

What’s a triad?

D Major - Open Position

The major and minor chords you first learn in the open position (the first four frets) on guitar are triads. A triad is a chord built from three notes, stacked in intervals of a third, as seen in our example on the left.

If you need to brush up on how to read a chord chart click here.

If you are wondering why many chords on the guitar seem to include more than three notes, it is because the notes are repeated e.g. a D Major chord includes the open D string and another D on the third fret of the B string.

Triads can be built using either scale degrees or intervals. Major and minor chords follow specific formulas based on these. So for example a major chord is built from the first, third, and fifth scale degrees of the corresponding major scale.

Alternatively, a diminished triad, if using intervals, consists of a root (the tonic note of the scale), a minor third, and a diminished fifth. Diminished means we are lowering the pitch of a perfect interval by a semitone, much like lowering the pitch of a major interval changes it to a minor.

The individual relationships between notes when building chords in this way are referred to as stacking thirds, as there is an interval of a third between each note included in the chord, another way to think of this is we are simply skipping every second note letter name.

So in the case of a D Major chord, we utilize the D (root), skip the E, include the F, (the major third) skip the G, and include the A (the perfect fifth).

Here’s another example using scale degrees:

D Major Scale

Scale Degrees1234567

Based on this we now know a D major triad uses the notes D (root), F#(third scale degree), and A (fifth scale degree), or root, third and fifth for short.

The third is important.  It determines if the chord is major or minor by the number of notes between the root and the third.

It’s important to remember, that we don’t count the notes of the scale when counting the notes between the root and the third, instead, we count the actual notes between them. With this in mind, we can see the F# is four notes after the D:  E.g. D, D#, E, F, F#

This is known as a major third interval and because this is the interval between the root and the third, the chord is therefore major.

When we flatten the third by a half step we end up with three notes between the root and the third, making this interval a minor third which makes the chord minor.

And that’s really all there is to how triads are built. Once you know the formula you can work out the notes in any major or minor triad relatively easily.

What are Augmented and Diminished Chords?
Diminished chords are composed of the root, a minor third, and a diminished fifth. A diminished fifth, simply means we flatten the fifth scale degree by a half step, meaning the third and fifth scale degrees now represent minor third intervals (3 notes, rather than a major third (4 notes). Augmented chords, on the other hand, raise the fifth scale degree by a half step. You might notice that augmented chords are often represented with a + for this reason.

* None of this is strictly essential to understanding what chords go together so don’t be concerned if you are unaware of what scale degrees and intervals are all about. Our articles on basic music theory for guitarists explain these concepts in simple, easy-to-understand terms if you want to learn more about basic music theory for guitar.

The Chord Scale

Unless you have memorized the notes in any given scale and the formulas used, it’s obviously not ideal to count the notes of the scale to work out the quality of a chord.

With this in mind, it’s simpler to focus on established patterns, for this, we reference the chord scale.

For example, in all major keys, the first, fourth, and fifth chords are always major. The second, third, and sixth are always minor and the seventh, which is built upon the 7th scale degree is diminished.

In minor keys the i, iv, and v chords are minor. The III, VI, and VII are major and the II is diminished.

The tables below show the chord names and qualities in more detail. Take note that minor chords are represented with lowercase Roman numerals, while major chords utilize uppercase.

Major Keys

B♭MajorC minorD minorE♭MajorF MajorG minorA diminished


Minor Keys

BBm C#dimDEmF#mGA
CCm DdimE♭FmGmA♭b♭
EEm F#dimGAmBmCD
FFm GdimA♭B♭mCmD♭E♭
GGm AdimB♭CmDmE♭F

So far this should all make sense with regard to chords that are within a given key, but when discussing chords, especially as part of a chord progression, we may also use the Nashville numbering system, as follows:

The Nashville Numbering System

D Major


This system known as the Nashville Numbering System was first developed in the 1950s to simplify the naming of chords within a sequence or common progression and is based on scale degrees.

While similar, the chords correspond with the numerals in the table above, just as our previous example used Roman numerals in upper and lower case. Also note, the lowercase ‘m’ and diminished symbol are used to denote minor and diminished chords.

Understanding which of these numbers in combination work well together is key to understanding what chords go together.

For example, the 1, 4, 5 chord progression is a particularly well-known three-chord formula that has been used extensively throughout music. And, one thing you might notice right away if you look back at the tables above, is I, IV, V are all major chords.

It’s important to understand when playing chords within a key, we use the major scale of that particular key. It doesn’t change when we play the II or IV chord for example.

So for example, if in the key of D again, if we are stacking thirds we are only using the notes within the key of D, e.g. the D major scale.

D Major Scale

Scale Degrees1234567

With this in mind, the I chord uses the notes D, F#, and A, making it a D major chord. If we take the II chord, however, we have the notes E, G, and B making the chord minor.

If instead, we were referring to the E major scale the notes would instead be E, G#, and B) making the chord major.

Chord Function (aka Harmonic Function)

Chords, when played as part of a progression such as I, IV, and V take on specific roles within chord progressions e.g. the I chord is the root, and therefore when we return to the I chord the progression resolves.

While the V chord (dominant) adds tension and feels like it must return to the I to resolve the chord progression.

Each chord in this regard has a function within a larger context and is used to define the movement of a larger chord progression, largely due to how specific notes color a specific chord. This is why some formulas work more effectively than others for specific genres.

If considering chords in a major key in this way there are six harmonic functions:

TonicSupertonicMediantSubdominantDominantSubmediantLeading Tone

These can be arranged into three specific groups: Tonic, Subdominant, and Dominant.

  • Tonic chords, are the chords that progressions resolve on and therefore create a mood of stability.
  • Dominant chords on the other hand create the opposite mood, resulting in tension and a need to resolve.
  • Alternatively, subdominant chords lie somewhere in the middle.

You can try this yourself by playing a simple I, IV, and V chord progression and noting the direction each chord feels like it is pulling you toward within the context of the chord progression.

Over time, especially when writing music you begin to notice that music is built upon a pattern of tension and release with everything really being about the journey to resolving the chord progression.

Chord Progressions

Now that we understand how to establish the letter names and qualities of chords within a specific key, and the role chords play within chord progressions we’ll finish this article with a look at some of the more common chord formulas used in music.

I, IV, V

Tonic > Subdominant > Dominant

The I, IV, and V chord progression is foundational and feels familiar because you have heard it many times.

It typifies tension and release within music, and is used to build the 12-bar blues (I, I, I, IV, IV, I, I, V, V, I, I) that more or less lead to modern pop and rock. Wild Thing by the Troggs is a well-known example of I, IV, V.

 I – V – VI – IV

Tonic > Dominant > Submediant > Subdominant

Perhaps the most overused chord progression in Western music, the sheer number of songs written using the I – V – VI – IV is remarkable.

In fact, if you haven’t seen ‘Four Chords’ by the Axis of Awesome, I have added it below and recommend you watch it. If you are unfamiliar with this ‘sensitive’ chord progression you will be amazed at just how many songs utilize it.

I–VI–IV–V (The 50’s progression)

Tonic > Sumediant > Subdominant > Dominant

Dating back to early classical music, the 50’s chord progression, as the name implies really took hold during the 50s. In fact, the I–Vi–IV–V typified pop music of the ’50s and ’60s, particularly doo-wop. Elton John’s crocodile rock is a good example.


Tonic > Dominant > Sumediant > Leading Tone

The I, V, VI, and VII have been used in music since the ’50s but are perhaps better known for their role during the ’90s in songs by artists such as Aerosmith and Kelly Clarkson.

Summary – finding chords that go together

Knowing what chords go together well, comes down to understanding how to identify the chords within a given key, the quality of the chord, and its role with regard to the movement it helps create within a chord progression.

And while you may prefer to write music in a less technical way, consider going back and looking at the music you might have previously written, you might be surprised just how much of the information above you have naturally used when composing music. Feel will always be the most important element when it comes to writing music, but knowing a few shortcuts doesn’t necessarily need to make your music feel more sterile, and in fact, may unlock musical directions you hadn’t considered previously.

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