The circle of fifths is an essential part of music theory. The circle of fifths provides a picture that is an easy to see complete set of rules for how to learn all of the major and minor scales.
The circle of fifths itself is the same as the circle used on an analogue clock face. Instead of being used to tell the time, it is used to show all the major and minor scales, and it goes in both directions, clockwise and anticlockwise. Also similar to a clock face, which has five-minute intervals around the clock, the distance between each scale is also an interval of five notes.
In the circle of fifths we give the scale names and we also provide the key signatures (sharps and flats) located on a musical stave. Starting at the top of the circle of fifths is the C major which does not have any sharps or flats. From the C major, moving around the circle of fifths, either left or right, the next key signature adds an extra sharp or flat, depending on the direction you are moving in around the circle of fifths. When you go clockwise, you go in the direction of increasing sharps up to seven sharps. The reason why you can go up to seven sharps is because there are seven notes in a scale, and every note can have a sharp. When you go anticlockwise, you go in the direction of increasing flats up to seven flats.
For each major scale, there is a minor scale with the same key signature. They are called relative scales because they share the same key signature. So at the top of the circle of fifths is the C major and it is also relative to the A minor. They are the same and both don’t have any flats or sharps. Minor scales are also moving in their own circle of fifths, following the same rules as the major scales.
Looking at the picture of the circle of fifths, the first sharp appears in G major that is located clockwise after C major. The key signature for G major is F sharp. The next scale is D major. In D major there are two sharps (F sharp and C sharp). Notice that the C sharp is the fifth note from F sharp. So all the sharps also are moving in their own circle of fifths. The flats in the key signatures also go by five notes going in an anti-clockwise direction.
The important rule is when you write the key signature it is different from the order of how you play the piano scale on the piano. You will always write the sharps in the order as they appear in the circle of fifths. For example, look at the A major scale on the circle of fifths. In the key signature there are three sharps that are written in the order of: F sharp C sharp G sharp. However, when you play scales, you will play: A B C# D E F# G# A.
It should now be very clear to you that the circle of fifths allows you to easily see all major and minor scales used in music. Knowledge of the circle of fifths is very important for every musician because it shows the foundation of major and minor scales.
