The circle of fifths is a visual representation of the keys you hear in music.
Starting at the top with the key of C major. Thus, the circle is split between the sharps (right side) and flats (left side) as we travel around it.
The Right Side of the Circle
Let’s start with the major keys on the right side of the circle.
It’s called the circle of fifths because the distance of a fifth interval separates each key signature (for example, C to G on the circle above represents a fifth).
Start at C major. Since there are no sharps in the key of C major, the notes in the key are C – D – E – F – G – A – B.
Now move to the next position on the circle, which is the key of G major.
Notice the outer ring of the circle has a new sharp
So the notes in the key of G major are: G – A – B – C – D – E – F#
Move another position to the right, and you see the key of D major has two sharps.
The next key, A major, has 3 sharps – and so on.
A sharp is added for every new fifth until we reach the bottom of the circle with the key of F#.
As you know from our discussion of “Enharmonic Equivalents,” the key of F# can also be interpreted as Gb.
The Left Side of the Circle
Instead of starting at the top, we’ll continue at the bottom with Gb.
Moving clockwise, the flats also move in order of fifths, just like the sharps, with one difference.
Instead of adding a flat every time, we remove one with every new key.
For example, The key of Gb has six flats, and Db has five, Ab has 4, and so on.
This pattern continues until we get back to the top of the circle with C major, which has no flats or sharps.