Triad Chord Theory

Learn the four types of triads and how to apply their formula to the Major Scale.

View the full lesson at Triad Chord Theory | JustinGuitar

Very nice and interesting course. Thank you Justin!

1 Like

I loved the augmented mystery expression hahahaha, that was CLASS, priceless & timeless!

1 Like

It’s soo cool seeing this stuff all start to come together, loving the theory course! :+1: :clap:

1 Like

Feeling the same way Fncanuk. It’s exciting to learn what we are and seeing previously mysterious terms start to make sense.


Is there an understandable reason, why no “double augmented” triad exists? If I look at the four triads, I automatically think, “why is there no triad with 1 / 3# / 5#?”

1 Like

Hi there,

Augmented triads already have two major 3rd intervals in them, so sharpening the first major 3rd by a semitone would raise it to a 4th, and the second one would become a minor 3rd.

That would make it a sus4 diminished triad, if that naming exists.


Ok, so I’m trying to work out the triads for all the major notes in the major scale. I’ve gotten to B and I’ve run into a hiccup. For the Augmented Triad, is it B, D, F## (or F*…or whatever the proper notation is) or would you say B,D,G?


1 Like

Hey Adam,

B Aug would be written B D#, F##

Cheers, Shane

1 Like

Hello @JanWartenberg and welcome to the community.
See if this helps.

If you look at the major scale formula, with C major below as an example, you can see that some notes are two semitones apart (a whole tone) and some just one semitone apart.
Between the 2nd and 3rd scale degrees there is a two semitone distance. Thus, the 3rd can be lowered (flattened) by a semitone and it does not encroach on the note below.
Between the 3rd and 4th scale degree is just one semitone. If the 3rd was raised (sharpened) it would occupy the same space as the note above it, the 4th. You could forcibly call it a #3 and view it as an enharmonic equivalent to the 4th scale degree. But that is not what happens. Instead, if the 4th scale degree is played within a chord because the 3rd has been raised, we call it the 4th and the chord becomes a sus4.
No such limitation applies to the 5th scale degree as there are two semitones either side of it so it can be flattened or sharpened.

Plus, as @Jozsef says, it is also the internal intervals that make up any chord. An augmented triad must contain two major 3rd intervals by definition.
I hope that helps.

Cheers :smiley:

| Richard_close2u | JustinGuitar Official Guide, Approved Teacher & Moderator

1 Like

Do you mean all notes in the chromatic scale? You are exploring triads for all 12 notes?

The D note should be D#, not D natural.

For augmented triads, start with the major triad and raise the 5th scale degree note by one semitone BUT keep the alphabetical letter name. You cannot call it by the next alphabetical letter name even if it has that as an enharmonic equivalent.

B major: 1, 3, 5 → B, D#, F#

B augmented: 1, 3, #5 → B, D#, F##

The double sharp symbol resembles a bold letter x if you see that written.

6 posts were merged into an existing topic: Theory course videos not working

When learning about the triads, I realised only the notes in the major tried fully belongs to the major scale. For the minor, augmented and diminished triads, some of the notes are not from the major scale. I would assume that the notes in the minor triad belong to the minor scale, but what about the augmented and diminished triads? Is it ok if the notes do not belong to any scale? Or do the notes belong to some other scale that’s neither major nor minor?

I had the impression that notes making up a chord should belong to the same scale.

1 Like

Hey Zach,

Yep there are scales like various diminished and augmented scales that feature these types of triads and beyond. Not really on my radar at present - perhaps @Richard_close2u will be along at some point to illuminate.

Re your thinking on the triad/ scale relationship etc, remember that every major scale produces 3 major, 3 minor, and one diminished triad. All the notes from all these chords are in the relevant scale, including the minors and diminished. They have to be, as their whole existence derives from these notes.
A triads membership of a scale however is not exclusive though. It can be a member of many scales, and chord families. Eg You’ll find every triad of C Major in A minor, cos they share exact same notes. They just function differently.

Cheers, Shane


Shane is correct on Major, minor and diminished chords, in the Parent Major and relative minor ssales. Augmented are a Major chord with a raised 5th so in theory you could find a mode that the chord fits into but it’s easier just to raise the 5th of the chord. Also augmented chords have a specific use and are not used very often in music.

1 Like

Hi everyone!

Just beginning to wrap my head around triads and I have a question of triads in a key. I was building major triads by first writing up the major scale for that note and then taking, the tonic, the third and the fifth.

But I was looking into harmonising the major scale and it seems cumbersome to build the major triad, then turn into a minor, or a diminished. Is it possible to build the correct triad from only the notes in the major scale?

Say: C D E F G A B C
C major= C E G
D minor= D F A???
E minor = E G B
F major = F A C
G major = G B D
A minor = A C E
B diminished = B D F

Are the above correct?

1 Like

Hey Gustavo,

Yes, the triads you have there are 100% correct. :+1:Thats how you ‘build’ the basic triads/ chords in a particular key.
Built from stacking 3rds together, as you’ve done. ie alternate notes.
Triads are always built from their parent scale. By definition, that is what triads/ chords are.
So, in any Major scale you always have;

Major triads - 1st, 4th, 5th
Minor triads - 2nd, 3rd, 6th
Diminished triad - 7th

Cheers, Shane


It would be incredibly helpful if you’d get some kind of camera on your fretting had, or at least diagrams of what you’re doing there. The majority of the time I cant tell and it takes a lot of time to figure it out.

1 Like

Richard has a really useful diagram here: Vintage Club 6 with Richard | Triads

This is from his triad overview session in the Club. This opened my eyes to using these in a way that the official lesson missed. Worth a read.


Had a very theoritical question. If i were to sharpen the 5th note of the minor would that theorically be an Augmented minor? Does something like this exist in theory at least?