Know your keys – just count 5!

The circle of 5ths (and 4ths)

keysKnowing your key signatures and understanding a few of the fundamental rules of key and harmony will allow for a greater awareness of the music that you play.  This article will delve into a little bit of music theory, if you find anything a little confusing please do comment below or just email me directly at and I will happily go through things with you.

Key Signatures, sharps, flats etc.

We will start with major keys, and will go from the key of C Major that has a key signature of no sharps or flats.  The circle of 5ths will give a clear and simple way of working out which keys have sharps or flats in, and how many they have.  It requires you to be able to count up to 5 and know your musical alphabet, (A, B, C, D, E, F, G and then back to A) and be able to start this on any note.

To make this work, it is going to be crucial to remember the following two points:

  1. That C Major has no sharps or flats in its key signature.
  2. When you count up in 5ths you need to include the note that you start on when you are counting. (More about this in a minute!)

We are going to work on the sharp key signatures first.  We are going to find the key that has 1 sharp.  We are going to use C Major to start with and count up 5:

1          2          3          4          5
C          D         E          F          G

Therefore, the key with one sharp is G Major.  The note that is sharpened in this key signature is F.  So G Major goes from G to G with an F sharp.  To get to the key that has 2 sharps, we need to count up 5 notes from G:

1          2          3          4          5
G          A          B          C          D

Therefore, the key with two sharps is D Major.  The notes that are sharpened in this key are F (as in G Major) and C.  So D Major goes from D to D with an F sharp and a C sharp.

So why is this called the circle of 5ths?  The key signatures are usually shown as a circle to make things easy to see and understand.

Here is the circle of 5ths completed with all of the sharp key signatures completed: Screenshot_18_07_2013_22_16

  • C Major = 0 sharps
  • G Major = 1 sharp (F)
  • D Major = 2 sharps (F,C)
  • A Major = 3 sharps (F,C,G)
  • E Major = 4 sharps (F, C, G, D)
  • B Major = 5 sharps (F, C, G, D, A)
  • F# Major = 6 sharps  (F, C, G, D, A, E)
  • C# Major = 7 sharps (F, C, G, D, A, E, B)

Flat Keys

To get the flat key signatures, instead of counting up 5 notes this time count up 4.  Again include the note you start with.  Starting again with C Major with no sharps or flats and then count up 4 notes:

1          2          3          4
C          D         E          F

So F major has 1 flat and the note that is flattened is B.  This means the F major scale goes from F to F with a Bb in it.  The next flat key is worked out in the same way.  Start with F and count up 4 notes:

1          2          3          4
F          G          A          Bb

So B flat major has 2 flats in it and the notes that are flattened are B and E.  This means B flat major goes from B flat to B flat with B flat and E flat in it.


  • C Major = No flats
  • F Major = 1 flat (Bb)
  • Bb Major = 2 flats (Bb, Eb)
  • Eb Major = 3 flats (Bb, Eb, Ab)
  • Ab Major = 4 flats (Bb, Eb, Ab, Db)
  • Db Major = 5 flats (Bb, Eb, AB, Db, Gb)
  • Gb Major = 6 flats (Bb, Eb, Ab, Db, Gb, Cb)
  • Cb Major = 7 flats (Bb, Eb, Ab, Db, Gb, Cb, Fb)

A simple way of remembering the order of the sharps and flats is by remembering this rhyme.  Take the first letter of each word for the note that will be a sharp or flat:

Father Charles Goes Down And Ends Battle

For flat keys, use the same rhyme in reverse:

Battle Ends And Down Goes Charles’ Father

The major scales are placed around the outside of the circle; watch out for the post on relative minor scales on Sunday.

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Know your keys – just count 5! — 2 Comments

  1. That’s really interesting and helpful, wish someone had explained it like this to me at the start! Thanks Shaun.

    • I learned this from the book “Music Theory for Dummies”, and as Helen said, I wish I’d known it long ago. I’m glad you are putting it out to we musicians.

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