The Circle of Fifths (also called the “Cycle of Fifths” or “Circle of Fourths”) is a powerful tool from music theory. It’s a way of thinking about the relationship between notes and chords that go together in music. Learning the Circle of Fifths helps you to more easily play by ear or improvise, by understanding the musical connections between notes and the chords.

The circle includes all 12 notes in the Western pitch system and arranges them in a musically meaningful way. The circle reveals how those notes (or chords, or keys) all relate to each other.

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Not just a theory

The Circle of Fifths isn’t just obscure music theory. In fact it’s a very practical tool.

You can use it to:

  • work out the notes in a scale as it reveals the key signature.
  • predict the next chord in a progression based on the arrangement of chords on the circle.
  • choose notes or chords when improvising from those near each other on the circle.
  • understand why certain notes and chords “go together” in music – great for song-writing!

So what is it?

The Circle of Fifths is simply a series of notes, arranged in a circle.

The series of notes increases by perfect fifths (e.g. C to G to D…), moving round like a clock and eventually ending up where it began (i.e. C).

The Circle of Fifths

If you go the other direction around the circle you get a series of fourths, hence the alternative name “Circle of Fourths”. This is because perfect fifths and perfect fourths are an inversion pair: Going upwards by one brings you to the same note as going downwards by the other.

Finding hidden keys

The arrangement of the circle means that it’s a handy way to figure out key signatures.

As you move clockwise from C, the number of sharps increases: from C (none) through G (1 sharp), D (2 sharps), etc.

As you move counter-clockwise from C, the number of flats increases: from C (none) through F (1 flat), B♭ (2 flats), etc.

The Circle of Fifths - Full

So if you know the key signature you can use the circle to figure out the key – and vice-versa!

Learn it fast

The Circle of Fifths is something which looks complicated but has a hidden structure that makes it easy to learn fast.

You just need to notice that it repeats: The letters on the left-hand side repeat the right-hand side (with added accidentals).

Just memorise this sequence: F, C, G, D, A, E, B

That’s it! Look again at the diagram and see how this sequence actually covers the whole circle.

A big payoff

Learning the Circle of Fifths pays off in many ways. It is definitely not just “theory for the sake of it”!

Learn the circle and you will find it comes up everywhere in your musical life. You will spot the circle in melodies, chords and harmony, improvisation and song writing. To learn more about how the circle can help you write music with real impact, check out our Ultimate Guide to the Circle of Fifths.