Has this happened to you? You’re writing a song and you’ve made a good start. The vocal melody is done and you’ve got a chord or two to match, but you just can’t seem to finish the chord progression. You keep trying all the chords you know, but nothing seems to fit. Eventually, you put the song idea aside and forget all about it.

What a waste! How many great songs never get finished because of this? Don’t let this happen to you when the solution might just be learning a little music theory—it’ll make those last chord choices a heck of a lot easier.

Now let me stop for one second to say something: music theory gets a bad reputation amongst some musicians, because sometimes it’s just not taught that well. If you’ve ever thought that music theory was a) just for classical musicians, b) for passing boring exams, or c) the opposite of creativity, then you may have just been taught it wrong. Let’s fix that. Music theory is awesome, and we’ll show you what it can do right now.

Let’s write a song

Here’s a melody I came up with for guitar. Super simple, right?

Next step is to add some chords. Let’s say I pulled up a huge list of chords from the web and just tried them randomly to see what fit. This could take a long while, and maybe I’d end up with something like this:

Hmm, that’s not sounding quite right. Now let’s try a music theory approach. The only terms that may be unfamiliar to you here are keys/scales (groups of notes that sound good together) and progressions (a set of chords, played one after the other). Ready?

Adding chords to a melody

1. Get the key. The notes in our melody are just C and D—super simple. Now, there’s something called a key in music, and it’s just a list of notes that sound good together. For this particular melody there are a bunch of keys that could work, but we’re going to pick the most obvious one: C major. (Play around with KeyFinder to see some others.) Alright, so the key of C major has just seven notes, and here they are:

C D E F G A B

2. Get the chords. Once you have a key, there’s a simple formula you can use to find seven chords that will fit well: M m m M M m dim (we’ll see an example below). Now, this isn’t a black-and-white process—sometimes the best musical choice is the most unexpected—but 9 times out of 10, you’ll find the chords you need here. This formula tells you which chords will be major, minor, or diminished, and here’s what you get for the key of C:

C major
D minor
E minor
F major
G major
A minor
B diminished

3. Write a chord progression. A “chord progression” is just a list of chords that you play, one after the other. You can start the progression with the first chord because it’s the most important one of the key, then follow your ear for the rest. (There are only six other chords, so just trying some different options won’t take long.) There are definitely going to be a few progressions that fit, and this comes down to musical choice. What do you like the sound of? That’s all that matters. Personally, I think the progression “C F” sounds good with the melody. Here’s what that sounds like (each chord is played twice):

Better, right? There are other ways to match chords and melodies, but this is one fantastic way that’s easy and works well. This is applied music theory—stuff for writing music, not exams—and if you want to learn more about it, you might want to check out the lessons in Waay. Here’s a preview:

Interested? Find out more here.

Music theory is awesome. It’s a toolbox to help you get your ideas out there, and it’s definitely not there to tell you what should sound good and what shouldn’t. That’s what your ears are for! Instead, it’s there to help you with chord choices, melody decisions, ways to build vocal harmonies, and more. Writing music is about realizing your musical vision and music theory is there to help.