What is a fifth?
In music theory, the distance between any two notes is called an interval. Intervals are measured in half steps, like feet are measured in inches, or pounds are measured in ounces.
One half step is the distance from one note to the next highest or lowest note. For example, the distance from C to C♯ is one half step higher. The distance from D to D♭ is one half step lower.
The interval of a fifth is equal to seven half steps. This concept may seem a little counter-intuitive; you might think a fifth should be five half steps, right? Let’s look a little closer.
Think about it like this. There are twelve notes in the musical alphabet:
C, C♯/D♭, D, D♯/E♭, E, F, F♯/G♭, G, G♯/A♭, A, A♯/B♭, and B
Even though there are seven half steps from C to G, G is only five letters away from C (C, D, E, F, G). Anything that is a distance of 5 letters apart is referenced in terms of a fifth. The same goes for the other intervals, but we will save that rabbit hole for another time.
Using the circle in your songwriting
One way to apply the circle of fifths in your songwriting is to fit the chord progressions you like onto the circle and then graft that same pattern onto a different location in the circle.
For example, take the chord progression from the beginning of “Smell Like Teen Spirit” by Nirvana: F5 – B♭5 – A♭5 – D♭5. How does this pattern fit on the circle? Let’s look into how the circle is constructed and see if we can answer that question. You can do this with any song or chord progression you like.
Using fifths to build the circle
The first step is to draw a circle and place 12 evenly spaced dots around the outside, like the numbers on a clock. Draw the letter ‘C’ at the top of the circle like this:
Key signatures and enharmonic equivalents
One of the main pieces of information contained in the circle of fifths is the progression of key signatures. Key signatures are another way to organize groups of pitches based on the number of sharp or flat notes in the set.
For example, the key of C major at the top of the circle does not have any sharps or flats. When we move clockwise around the circle, we add sharps to the key signature. Thus the key of G major has one sharp, the key of D major has two sharps, the key of A major has three sharps, etc.
This pattern continues until we reach the key of C♯ major, which has seven sharps. At this point, all the notes in the major scale are sharp, so if we wish to continue, we will need to add double sharps. Double sharps are sort of challenging to think about quickly, so most people will switch to flat keys here using the concept of enharmonic equivalents.
Enharmonic equivalents are two notes that share the same pitch. For example, C♯ and D♭ are the same pitch but are different notes. G♭ and F♯ are different notes but the same pitch. These notes are called enharmonic equivalents.
Using enharmonic equivalents to complete the circle
C♭ is the enharmonic equivalent of B. Mark C♭ on the inside of the circle like this:
Now, we can continue clockwise around the circle with the flat keys. Count up seven half steps from C♭ , and you find G♭. Count up another seven half steps, and you will reach D♭. Another seven half steps bring you to A♭. Seven half steps above A♭ is E♭, seven half steps above E♭ is B♭, seven half steps above B♭ is F, and finally, seven half steps above F brings us back around to C. Now your circle should look like this:
Congratulations! You have successfully constructed the circle of fifths!
Some basic patterns on the circle
Picking up where we left off
Beginning on the F chord, move one step counterclockwise to B♭. Then, you jump to A♭ and move one step counterclockwise to D♭. See if you can trace this pattern on your circle, it should be pretty straightforward to see. Now let’s mess around with it.
Can you construct this same pattern beginning from D? The pattern would be D – G – F – B♭. Now, vary the tempo, change the quality of chords to minor or major, or add extensions like the 9th or 11th, so the progression does not sound too similar. Simple, right?
You can take this approach with just about any song. You will find that most popular chord progressions fit nicely on the circle of fifths.
Grow your own
You can also use the circle as a tool to build your own chord progressions. For example, begin at G minor. How does it sound if you move from G minor one step clockwise to D major? What about D minor? From there, what if you move across the circle to F major—followed by F minor? Then move clockwise to C and finally back to G minor?
What about if you start with E major and skip steps moving counterclockwise? E major – D major – C major – B♭ major – A♭ major? Sounds pretty dramatic. Maybe you cut it down to E major – D major – C major? See how this structure can provide infinite room for experimentation and exploration? Your imagination is the only limit.