One little secret hidden within the Circle of Fifths, is that it shows you all of the major and minor chords in any key. First, let’s look at the key of C, which is at the top of the Circle of Fifths.
In any major key, the three major chords are the I chord, the IV chord, and the V chord. You’ll see C major, which is our I chord in the key of C. We go to the left on the circle to see our IV chord which is F, and then to the right to see our V chord, which is G.
Now, right below the C, we see the relative minor of the key of C, which is Am. The Am is also the vi chord. The other two remaining minor chords are the ii chord, which is D minor, and which we can see to the left of the Am, and the E minor, which is to the right of the Am.
The only chord in a key that is not shown is the diminished chord. In a major key, this chord is not used very often, but if you want to find it, just go down one half step from the tonic. For instance, down one half step from C, is B, so your diminished chord would be B diminished. The diminished chord is the vii chord, or the last chord in the key.
Now let’s look at this in the key of G. As you can see, the I chord is G, the IV chord is C (to the left), the V chord is D (to the right), the vi chord is Em (directly below), the ii chord is Am (to the left of Em), and the iii chord is Bm (to the right of Em).
Hopefully you now understand how you can use the Circle of Fifths as a reference to memorize all of the major and minor chords in any of the 12 keys. These chords will all sound great together in any order. This doesn’t mean you have to constrain yourself to these chords, but they will be the standard collection of chords used in any key!
0:00 - Intro
0:43 - I, IV, V
3:15 - Minor Chords
5:53 - Examples
6:49 - Outro