The Circle of Fourths (also known as the Circle of Fifths) is a visual representation of the 12 notes in Western music. It’s a handy tool for musicians trying to understand the relationships between keys and chords.
In this article, we’ll break down the Circle of Fourths, how it’s constructed, and how you can use it to improve your music.
You might be wondering, “Wait, is it the Circle of Fourths or the Circle of Fifths?” While both terms are used, this article will explain both concepts while focusing primarily on the Cycle of Fourths and how it can help you write songs and understand music theory.
What is the circle of fourths/fifths?
The circle of fourths (or fifths) is a visual tool that shows the relationships between musical keys. The circle illustrates how keys relate to each other based on intervals of perfect fourths or fifths.
The circle is a cyclical tool that starts with C and then moves around the circle, showing keys that are a fourth or fifth apart from each other.
The circle of fourths/fifths relates to the 12 tones of the chromatic scale and helps musicians understand key signatures and the relationship between major and minor keys.
How does the circle of fourths work?
The circle of fourths is a way of visualizing the relationships between musical keys. It’s a tool that can help you understand key signatures and how keys relate to one another. Here’s how it works.
Constructing the circle of fourths
The circle is built on the interval of a perfect fourth. Start with the key of C, then move up a perfect fourth to F. From F, move up a perfect fourth to B♭, and so on. Keep going, and you’ll eventually cycle through all 12 keys and end up back at C.
You can also create the same cycle by moving in descending perfect fifths. This is useful for understanding the relationship between fourths and fifths.
Understanding key signatures
As you move clockwise around the circle (in fourths), you add flats to the key signature. As you move counter-clockwise (in fifths), you add sharps to the key signature. The key of C major has no sharps or flats.
Enharmonic equivalence
Some notes have two names (for example, F♯ and G♭). This is called enharmonic equivalence. Understanding enharmonic equivalence is important for navigating the circle, as it allows you to move smoothly between keys that might otherwise seem unrelated.
Circle of Fourths vs. Circle of Fifths
The circle of fourths and the circle of fifths are essentially the same thing. They both illustrate the relationships between musical keys.
The only real difference is the direction you move around the circle. If you move clockwise, you’re ascending by fourths. If you move counter-clockwise, you’re ascending by fifths.
The circle of fifths is more commonly used, but the circle of fourths can be a useful tool, too.
Practical applications of the circle of fourths
The circle of fourths isn’t just a pretty diagram; it’s a handy tool for musicians. Here’s how you can use it.
Chord progressions
Chord progressions often move in ascending fourths (or descending fifths, depending on how you look at it). You’ll see this pattern repeated throughout music history.
One example of a chord progression moving in fourths would be C – F – Bb – Eb – Ab – Db – Gb – B – E – A – D – G. It’s a pretty progression, and it’s the basis for songs like:
- “Confirmation” by Charlie Parker
- “Layla” by Derek and the Dominos
- “Island in the Sun” by Weezer
- “(I Can’t Get No) Satisfaction” by The Rolling Stones
- “Yellow Submarine” by The Beatles
Transposition
Need to transpose a piece of music to a different key? The circle of fourths can help you visualize the relationships between keys and make the process easier.
Improvisation
The circle of fourths can also help you figure out which keys are related to the one you’re in, which can be useful when you’re improvising. It also helps you identify which scales are suitable for improvising in a particular key.
Understanding related keys
Keys that are close together on the circle are considered “closely related.” This is helpful for modulation (changing keys within a song) and creating smooth transitions between different sections of a piece.
Major and Minor Scales on the Circle of Fourths
The Circle of Fourths is a useful tool for understanding major and minor scales in music theory. Major scales, for instance, always follow a specific pattern of whole steps and half steps (W-W-H-W-W-W-H). You can use the circle to see how the complexity of the scales increases as you move away from C major, which has no sharps or flats.
The Circle of Fourths can also help you identify relative minor keys. Each major key has a corresponding minor key (its relative minor) that shares the same key signature. By understanding the Circle, you can quickly determine the relative minor of any major key and vice versa.
Memorizing the circle of fourths
Here’s how to learn the circle of fourths quickly:
- Imagine a clock face. Think of C as being at the 12 o’clock position. Then, Eb would be to the right, and so on.
- Memorize the key landmarks. Start by learning C, Eb, F#/Gb, and A.
- Recite the cycle aloud. Keep repeating it to yourself until you can rattle it off without thinking.
- Use a printable diagram. Keep a PDF nearby for quick reference.
Why “Cycle of Fourths” Might Be a Better Term
Some musicians and music theorists prefer the term “cycle of fourths” instead of “cycle of fifths,” and here’s why.
Chord progressions commonly move in ascending fourths, which is why you’ll see the interval of a fourth so often in pop music.
Practicing scales and chord changes in the cycle of fourths is a great way to learn to play in all keys, and it gives you a more interesting and varied approach than simply going up or down by half-steps.
The Bottom Line
The Circle of Fourths (and Fifths) is a powerful tool for any musician. It gives you a visual representation of the relationships between keys, chords, and key signatures.
If you memorize and apply the Circle of Fourths, you’ll deepen your understanding of music theory and become a better musician overall.