Circle of Fifths Explained

Circle of Fifths Explained

The “circle of fifths” is shown above and has the note of C located at the uppermost position.  This C note represents the C major scale:
Key of C: C • D • E • F • G • A • B • C

Each musical note in this scale can be assigned a number as follows:
Key of C: C1 • D2 • E3 • F4 • G5 • A6 • B7 • C8

The key of C is the only musical key that has no sharps or flats.  As we go around the circle in a clockwise direction, the number of sharps increases by one.  As we go in the counter clockwise direction, the number of flats increases by one.  The circle therefore helps us to define a song’s key signature by observing the number of sharps or the number of flats.

As we go around the circle in the clockwise direction, the increment for each step is “five”; hence the term circle of fifths.  Therefore starting at the key of C at the top, we can find the key signature that has one sharp and that occurs next in the circle of fifths by counting five notes ahead in the C scale.  C1 • D2 • E3 • F4 • G5; therefore the next note in the circle of fifths is the G note and the G scale has one sharp.  We now count five in the scale of G to find the next note in the circle that will also be the key signature that has two sharps.  G1 • A2 • B3 • C4 • D5; therefore the next note in the circle of fifths is the D note and the D scale has two sharps.  This process continues until you get to the key of B which has five sharps.

As we go around the circle in the counter clockwise direction, use four as your increment instead of five.  Therefore starting at the key of C at the top, we can find the key signature that has one flat and that occurs next in the circle of fifths by counting four notes ahead in the C scale.  C1 • D2 • E3 • F4 ; therefore the next note in the circle of fifths in the CCW direction is the F note and the F scale has one flat.    This process continues until you get to the key of D flat which has five flats.

The graphic at the top of this post also includes the minor keys inside the circle of fifths.  As you go around the minor circle of fifths, you will note that the lettering sequence is identical but that it has been shifted counterclockwise by three.

From the circle of fifths, we can see the following:
C Major & A minor have ALL naturals
G Major & E minor have 1 sharp: F#
D Major & B minor have 2 sharps: F# and C#
A Major & F# minor have 3 sharps: F#, C# and G#
E Major & C# minor have 4 sharps: F#, C#, G# and D#
B Major & G# minor have 5 sharps: F#, C#, G#, D# and A#
F# Major & D# minor have 6 sharps: F# • C# • G# • D#• A# • E#

As a guitarist, you can improvise along a song in the key of Am by using a C major scale.  Likewise, a song in Em can be enhanced by improvising over the G major scale and so forth.  From the circle of fifths, you can see that keys are related to each other not by their relative position in the chromatic scale but by their relative position on the circle of fifths.

So the circle of fifths helps us to identify key signatures and also to find related keys, particularly in comparing minor and major keys.

Now apply what you’ve learned.  Using your right hand, five fingers, count off each key signature and identify the number of sharps and flats.  It’s easy.   Here goes:
Key of C – no sharps or flats by definition.
CDEFG – key of G has 1 sharp.
GABCD – key of D has 2 sharps.
DEFGA – key of A has 3 sharps.
ABCDE – key of E has 4 sharps.
EFGAB – key of B has 5 sharps.

Now count in fourths to find the flat signatures:
Key of C – no sharps or flats by definition.
CDEF – key of F has 1 flat.
FGAB – key of Bb has 2 flats.
BCDE – key of Eb has 3 flats.
EFGA – key of Ab has 4 flats.
ABCD – key of Db has 5 flats.

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3 thoughts on “Circle of Fifths Explained”

  1. Hey there, this is a quote you wrote from above. “Likewise, a song in Em can be enhanced by improvising over the A major scale and so forth”. Don’t you mean Em can be enhanced by improvising over the G major scale?

    Am I missing something

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