# Music Theory intervals lesson part 4 – The Circle of fifths (with audio)

The Circle of fifths is a circle of closely related pitches or key tonalities. It shows how the different keys are related to one another. It is usually shown as a circle with the names of keys around it. If you take any key in the circle, its fifth is the one to its right. It can be easily understood together with a piano keyboard. The
letters on the ring refer to major key names and chord roots. The
letters on the inside ring refer to minor keys and chord roots. The
rings are arranged so that the major keys are adjacent to their relative
minor
counterparts. For example, A minor (in the inner ring) is the
relative minor of C major
(on the outer ring).

Each time we went to a sharper key we took the note which was the 5th note of the previous scale (G, with one sharp, was the 5th note of C major. D, with two sharps, was the 5th note of G, etc).
In a diagram this can be shown as a circle which is called the “Circle of Fifths”. As each scale gets more sharps we go clockwise round the circle. Below is a video on this:

Circle of fifth progression – Clockwise and ascending (Quicktime player need. Download here)

Circle of fifth progression – Anticlockwise and decending (Quicktime player need. Download here)

Starting at any pitch, ascending by the interval of an equal tempered
beginning pitch class. At the top of the circle, the key of C Major has no sharps or flats. Moving clockwise on the circle, we go from C to G to D, etc.
This movement can be interpreted in two ways. First, if we are going up
the scale, the interval from C to G is a fifth. Second, if we are going
down the scale, the interval from C to G is a fourth.
Crucially, when moving clockwise it is by ascending fifths. This means each key that moves up by a fifth will also gain extra sharps each time e.g.
1. C, d, e, f…
2. G, a, b, c…(5th from C – one sharp)
3. D, e, f, g… (5th from G  – two sharps)
4. A, b, c, d (5th from D – two sharp)
5. E, f , g , a …(5th from A – one sharp)
6. B, c , d , e. . (5th from E – five sharps)
7. F , g♯, a♯, b…(5th from B six sharps)
8. D♭, e, f, g… (5th from F  – no sharps/flats)
9. A♭, b♭, c, d♭…(5th from D one flat)
10. E♭, f, g, a♭… (5th from A – three flats)
11. B♭, c, d, e♭…(5th from A two flats)
12. F, g, a, b♭ …(5th from  B♭ – one flat)
13. C (5th from  G – two sharps)
Similarly, if we move counter-clockwise around the circle of
descending fifths from C to F to Bb, this movement can be interpreted in two ways.
First, if we are going up the scale, the interval from C to F is a
fourth. Second, if we are going down the scale, the interval from C to F
is a fifth.
At the bottom of the circle, the sharp and flat keys overlap, showing pairs of enharmonic key signatures sharing the
identical tone. For instance, the key of C♭ has seven flats while the
key of B has five sharps. Yet, since they refer to the same note, they
are tonally equivalent.
To pass the twelve tones counterclockwise, it is necessary to ascend by perfect fourths, rather than fifths. (To the ear, the sequence of fourths gives an impression of settling, or resolution.

Circle of fifths are useful because:

• Dominant 7th chords
(which are common in popular music), have a tendency to move towards (also known as ‘resolve’) certain chords. But which chord is next? The
answer is simply to go down a fifth, or counter-clockwise on the circle.
So if a piece of music has a G7 chord at the end of a bar/the music, it will resolve onto a C. If we use an F7, it will resolve onto a B♭.
• In a lot of music, the most common chords will be those
of the key the music is in, and the chords on either side of it on
the circle. For example, if you are playing in the key of C, you’ll
likely use F (the subdominant) and G (the dominant) as well.
• When writing songs,
sometimes it can be hard to come up with interesting chord progressions. We can use the chart for this by experimenting with moving between relative majors and minors or jumping by a fourths/fifths. Jazz and (especially) Blues sometimes use the circle of fifths in their progression.