Finding Chords In A Scale: Intro To Diatonic Chords
- Yash
- Dec 24, 2022
- 5 min read
In any scale, the diatonic chords are chords that "belong" to that scale because the notes that make them up (Chord Tones) are strictly from the scale.
In this article, I will focus on finding the diatonic chords of the Major scale to lay the foundation. You can read my post on Harmonic Minor to see how this concept is applied on more advanced scales.
It would help in understanding this article if you understand what are musical intervals.
Finding diatonic chords
To find the chords in a major scale, we follow the concept of stacking thirds. It means we start on any note of the scale, then find the note on the scale that is the 3rd interval above our starting note.
Then we find the 3rd interval above the second note. In this way, we are stacking these notes above one another that are 3rd intervals away from each other.
If you stack three notes in this way, you have made a Triad. These are the most basic form of chords.
Technically, you can pick any three notes from the scale and call it a chord, but we use this method because notes chosen at random might not necessarily be useful. This way of constructing triads has been proven to work through years of experimentation by composers.
In the major scale, the third interval can simply be found by looking at every other note.
Let's learn this with an example.
Diatonic triads of a Major Scale
Here's the C Major scale with its scale degrees.
1 | 2 | 3 | 4 | 5 | 6 | 7 |
C | D | E | F | G | A | B |
We will form triads starting on each note of the scale and then stack thirds on it.
The first chord would start on C, and then the notes stacked on it would be E and G.
The second chord would start on D, and then the notes stacked on it would be F and A.
We do this for the rest of the notes and get this list:
1. C-E-G
2. D-F-A
3. E-G-B
4. F-A-C
5. G-B-D
6. A-C-E
7. B-D-F
So now we have a list of triads, but we have no idea what their names are. For this, we need to understand what are the types of triads.
Types of triads
As we discussed, a triad is made by stacking 3rds. However, a 3rd interval can be Major or minor. So that gives us multiple ways of arranging the three notes of the triad, depending on the quality of 3rd interval used each time(M3 - M3, M3 - m3, m3 - M3, m3 - m3)
And since we have three notes in the chord, the first and third notes will also have some interval between them. This turns out to be some kind of 5th. It can be diminished, perfect, or augmented 5th.
Therefore, we can conclude that a triad is made up of Root, 3rd, and 5th.
In case you don't know the difference between major 3rd and minor 3rd, read this.
Every interval is made of two parts: The number of the interval and the quality of it. The number can be figured out by counting the letters as we go from one note to the other.
Once the number is figured out, we can then decide the quality of interval by counting the semitones between them and then flattening or sharpening the letter to achieve the desired interval.
So for example, from F to A, there are three letters. So it is a 3rd interval. Now we figure out whether it is major or minor using this rule:
Major 3rd interval is made up of four semitones (half steps) between notes and the minor 3rd is made up of three semitones. In other words, minor 3rd is a semitone below the major 3rd.
Between F and A there are four semitones, so it is a major 3rd interval.
To make it minor 3rd, we would need one less semitone, and we can get it by flattening the A. Therefore, the minor 3rd interval from F would be A♭.
*If we used G♯ instead of A♭, it would still have 3 semitones, but now there are 2 letters from F to G, so it is not a 3rd interval anymore despite being the same pitch.
Open this to see the different kinds of 5th intervals
As the name suggests, 5th interval needs to have five letters from one note to the other.
Then, if there are 7 semitones between them, it is a Perfect 5th
If there are 6 semitones it is a diminished 5th
If there are 8 semitones, it is an augmented 5th.
In other words, you get diminished 5th by flattening the perfect 5th and augmented 5th by sharpening perfect 5th.
There are four types of triads: major, minor, augmented, and diminished.
Here are all of them using C as the Root:
Quality of diatonic triads in the major scale
Using this info about triads, we can figure out the full names of the diatonic triads in a major scale.
Root On | Notes | Name Of Chord | Roman Notation |
C | C - E - G | C Major | I |
D | D - F - A | D minor | ii |
E | E - G - B | E minor | iii |
F | F - A - C | F Major | IV |
G | G - B - D | G Major | V |
A | A - C - E | A minor | vi |
B | B - D - F | B diminished | vii° |
Since all major scales are made up of the same intervals, this order remains the same in all of them. So the first chord of all major scales is major, the second chord is minor, the third is minor, and so on.
Major, minor, minor, Major, Major, minor, diminished.
As we see here, we don't have any F♯, so the D Major chord is not diatonic to the C Major scale.
If you don't know what those roman numbers are doing there, I'd recommend that you read my post on the roman numeral notation of chords.
Diatonic Suspended chords in the major scale
So far we have seen only the triads based on 3rd interval stacking but there is another category of 3-note chords called Suspended chords.
A Triad is made up of Root, 3rd, and 5th as we saw before. Suspended chords have a different structure. They are of two types: Sus2 and Sus4.
Here are the intervals used to make both of these:
As you see here, they still contain the 5th interval, but the 3rd gets replaced by either Major 2nd or Perfect 4th.
This results in the chord feeling as if it is hanging there without any particular major or minor sound.
Open this to learn about Major 2nd and Perfect 4th intervals
The major 2nd interval is made up of two semitones (or a tone). As the name suggests, it needs to have two letters. For example: C and D, F and G. E and F is a minor 2nd interval because even though it does have two letters, there is only one semitone between them.
Perfect 4th interval has four letters and five semitones. Example: C and F, G
In a major scale, not all roots can give us suspended chords because sometimes we don't have the proper intervals available. Let's see this by taking each note in the C Major scale as a root and figuring out which sus chords can be made.
I would recommend that you read the first three of these explanations and try to figure the rest out on your own.
Root on C
The 2nd interval that we have is Major 2nd (C to D). The 4th interval is Perfect 4th (C to F) and the 5th interval is Perfect 5th (C to G). This means that we can have both Csus2 and Csus4 chords diatonic to the scale.
Root on D
The 2nd interval is E, the 4th is G and the 5th is A. They are Major 2nd, Perfect 4th, and Perfect 5th, so again, we can have both Dsus2 and Dsus4 chords.
Root on E
The 2nd interval from E that we have available in the scale is the minor 2nd because F is just a semitone away from E. The 4th and 5th are perfect. Therefore only Esus4 is diatonic to scale.
Root on F
The 2nd interval is a major 2nd, but the 4th interval is not perfect (Between F and B). The 5th is perfect. So, only Fsus2 is available.
Root on G
Here all the required intervals are available, so we can have Gsus2 and Gsus4.
Root on A
Again, both Asus2 and Asus4 are possible.
Root on B
In this case, the 5th interval is a diminished 5th. So neither of the sus chords is possible because they both require a perfect 5th.
Here is a table showing which suspended chords are diatonic to the major scale.
Root On | Sus Chords |
1 | Isus2, Isus4 |
2 | IIsus2, IIsus4 |
3 | IIIsus4 |
4 | IVsus2 |
5 | Vsus2, Vsus4 |
6 | VIsus2, VIsus4 |
7 | - |
Diatonic 4-note chords
We have seen how to find 3-note diatonic chords. Now let's take it one step further and find out the 4-note chords. For this part, I will not be getting into the details about naming these chords so I suggest you read this article about the various types of 4-note chords.
The concept remains the same as before. We stack 3rds, but instead of stopping at three notes, we add another 3rd interval on top of the triads.
This will give us four notes in each chord. Let's mix things up by taking the A Major Scale as an example.
1 | 2 | 3 | 4 | 5 | 6 | 7 |
A | B | C♯ | D | E | F♯ | G♯ |
Just like we did for triads, let's start with each note of the scale and stack 3rds till we get four notes.
If the Root is A, we will get A - C♯ - E - G♯. Counting each of these note intervals from the root, we get Root (A), Major 3rd (A to C♯), Perfect 5th (A to E), and Major 7th (A to G♯).
This is the AMaj7 chord.
Starting on B, we have B - D - F♯ - A. The intervals here are Root (B), minor 3rd (B to D), Perfect 5th (B to F♯), and minor 7th (B to A). These intervals make up the Bmin7 chord.
Repeating this process for all the notes, we get this list:
Notes | Roman Notation |
A - C♯ - E - G♯ | I Maj7 |
B - D - F♯ - A | ii min7 |
C♯ - E - G♯ - B | iii min7 |
D - F♯ - A - C♯ | IV Maj7 |
E - G♯ - B - D | V7 |
F♯ - A - C♯ - E | vi min7 |
G♯ - B - D - F♯ | viiø7 |
Diatonic chords in a minor scale
To practice the concepts that we have learned, let's try to do the same thing for the minor scale using E minor as an example. (Again, this will apply to all minor scales since they are made up of the same intervals.)
1 | 2 | ♭3 | 4 | 5 | ♭6 | ♭7 |
E | F♯ | G | A | B | C | D |
I recommend that you try this on your own first before looking at the results.
Open this to see the answers
Minor (i)
Diminished (ii°)
Major (♭III)
Minor (iv)
Minor (v)
Major (♭VI)
Major (♭VII)
Conclusion
Diatonic chords are chords that are made using the notes in a scale.
The order of chords in a major scale is: Maj min min Maj Maj min dim
Sus chords are possible with some of the notes as roots but not all.
Here are the diatonic 7th chords in a major scale:
I Maj7, ii min7, iii min7, IV Maj7, V7, vi min7, viiø7
To learn about the diatonic chords of modes of the major scale, read my post on Modes. I
Thank you for reading this post. If you are interested in learning more about music, do subscribe to the blog, or reach out to me directly at iriscryptmusic@gmail.com.
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