Music Theory Basics: Triads

Triads are the basic building blocks of Western Music.

Triads form the basic chords that are extensively used in the music that you and I listen to.

A triad is formed from three notes. If you are not too familiar with intervals, you may want brush up on them.

When forming any triad, we start with a root note, which we label as 1.

Major Triads

The major triad has a root (1),  major third (3) and a perfect fifth (5).

We can abbreviate these intervals with their numbers, and create a chord formula:

Major chords: 1 3 5

Minor Triads

A minor triad has a root (1), minor third (b3) and a perfect fifth (5). Minor chords have the following formula:

Minor chords: 1 b3 5

Diminished Triads

A diminished triad has a root (1), flat third (b3) and a diminished fifth (b5). Diminished chords have the formula:

Diminished chords: 1 b3 b5

Augmented Triads

An augmented triad has a root (1), major third and an augmented fifth (#5). Augmented triads have the formula:

Augmented triad: 1 3 #5

Diminished and augmented triads are both what we call “symmetrical chords”.

Working Out Some Examples

If you are new to thinking about intervals, you will probably find it easiest to think about them referencing your guitar. Make sure you know where the notes on your guitar neck go, if not, find yourself a neck diagram to check.

Let’s work out an example for each of those four triads, using the note A as the root note.

We are going to work along a single string.

We will start with the A major triad.

Start by finding the note A somewhere on your guitar:

Remembering the chord formula for a major triad of 1 3 5, we next need to find a major third from the A (the ‘3’ in the formula). The major third is 4 frets higher than the root:

C# is a major third higher than the note A

The last part of the chord formula for a major chord is the perfect fifth, ‘5’. The perfect fifth in a major chord is 7 frets higher than the root note. Starting with the note A, find the perfect fifth on the guitar string like this:

E is a perfect fifth higher than A. Here they are marked on the guitar

Having all three notes at once on the string:

The notes for an A major triad marked on the neck

So the notes in an A major triad are: A C# E.

That’s how you work it out :) See if you can work out what the notes in an A minor, A diminished and A augmented triad are.

Here are the answers:

A major: A C# E

A minor: A C E

A diminished: A C Eb

A augmented: A C# E#

How To Practically Apply This

Ok so working out the notes for these triads is great, but what is the purpose behind figuring this out? How do you play an A minor triad?

Any time you play those three notes in an A minor triad (A C E) on your guitar (or any instrument), you are playing an A minor triad.

This way of playing it is probably familiar to you already:

However, we could also play an A minor triad like this:

Playing an A minor triad on guitar using a barre chord

Or in these following ways:

These are all equally valid ways of playing A minor on guitar. They all sound very different.

If you want to change these A minor triads to A diminished, remember the chord formulas:

A minor: 1 b3 5

A diminished: 1 b3 b5

We can see that the difference between the minor triad and diminished triad is the 5th. So to change the A minor into an A diminished, we replace the E, with Eb. Go back to the diagrams and work this out.

Playing These Chord Shapes

Being able to work out these chords out is a valuable skill for any guitar player. They give you ways to make even simple chord progressions sound beautifully hypnotic and complex.

Treat figuring out these triads as a theory exercise. Pick a couple of them and train them into your playing.