When I was first learning how to compose music, one of the most frustrating things to figure out was how to write an effective chord progression. I could figure one out through trial and error, but I wanted to know why some chords seemed to go together and others didn’t. Eventually, I learned that the secret has to do with something called functional harmony.
Writing a Chord Progression is deceptively simple when using functional harmony, and can be done in just 5 steps!
Start by picking the key you want to write in.
Identify the chords available in that key, and their functions (Tonic, Subdominant, or Dominant)
Start your chord progression with the chord your key is named after (a.k.a the tonic chord).
Pick the cadence you want to end your chord progression with.
Fill in the remaining space using a pattern of “strong-weak” or “T-SD-D” until the pattern is interrupted by your cadence.
Picking a Key to Work With
Your key is essentially whichever major or minor scale you use to write your music. Choosing which specific key to use isn’t too important at this stage, since you can always change it later. For now, we just need to make sure we know which notes belong in each key.
If we look at the C major scale, we can see that it contains the notes C, D, E, F, G, A, and B, before repeating
If we look at the distance between these notes on a keyboard, we see that the order of intervals between each note follows a pattern. We have a whole step from C to D, another whole step from D to E, then a half step from E to F, three more whole steps connecting F, G, A, and B, and finally another half step to bring us back to C. All in all, we have a pattern of W-W-H-W-W-W-H.
This same pattern can be used to find any given major scale! Just pick a note to start on, and follow the pattern from there! For example, If we Start with D natural and follow our pattern of whole and half steps, we get the D major scale!
The same goes for G natural, Bb, or any other note you'd like to start with. You'll always get a major scale!
We can use a similar idea to find the minor keys. Just pick any random note and follow the pattern of W-H-W-W-H-W-W to find something called the “natural minor” scale!
(there are other types of minor scales but we won’t need to worry about them just yet).
For example, if we start on A natural, and follow our new pattern, we find the "A natural minor" scale.
Identifying the Chords in a Key
Once you have your key picked out, the next step is to identify which chords belong to it.
For this, all we need to do is follow the “add, skip rule”. This rule is very simple, it means we start with one note and add it to your chord, skip the next note in the scale, and add the third, then we skip the next note, and add the fifth.
Starting with the first note in the C major scale gives us a C major triad, where the 1st = C, 3rd = E, and 5th = G. This is the chord that the scale is named after!
We know it’s C major because the interval between the first two notes (C and E) is a Major third, or 4 half steps; while the interval between the second two notes (E and G) is a minor third or 3 half steps. This combination of a major third on the bottom and a minor third on top is what makes a major triad a major triad.
If we follow the same “Add-skip” rule for the rest of the scale; we can build the next chord by starting with the 2nd scale degree, skipping the next note, adding the third, skipping the fourth, and adding the 5th. This gives us a D minor triad.
We know it’s a D minor triad because the distance between the first two notes is a Minor 3rd, and the distance between the second two is a Major 3rd. This is the opposite of the Major triad and is what defines a minor triad.
Following this same pattern, we can find the remaining triads in our key! Put together they are C major, D minor, E minor, F major, G major, A minor, and B diminished (a diminished triad is made up of two minor 3rd intervals stacked on top of each other).
The cool thing about this is that since all major scales follow the same pattern of intervals, they also share the same exact pattern of chords!
1. The first chord will always be a major triad
2. The second and third chords will always be a minor triad
3. The third chord will always be a minor triad
4. The fourth and fifth chords will always be major triads
5. The sixth chord will always be a minor triad
6. The seventh chord will always be a diminished triad.