Key Signatures

All major scales are identified by their unique signature. That is, each scale is known by the accidentals that are generated by the strict pattern of half-steps and whole-steps, that controls all major scale construction.

This identifier is referred to as the Key Signature . It is important from the outset to both understand and memorise the key signatures for all keys. This will assist in quickly determining which notes of a major scale are altered by sharps or flats. This makes it possible at a glance to recognise the key of a piece by both the distinct order and number of accidentals within the key signature.

How Do We Work With Key Signatures?

There are fifteen key signatures in total. Seven sharp keys, seven flat keys and one natural key. Key signatures to musicians
are what times tables are to mathematicians. Committing your key signatures to memory as you would your times tables, allows you
to easily solve musical problems. Your knowledge of keys is your basis to unravelling and solving musical questions.

Lets detail the key signature for each major scale and examine how they relate to other major scales.

C major is a natural key and contains no sharps or flats.

The Importance of C Major

C major is a special key. It is the only key that does not contain sharps or flats.

It is so special, that if you consider the keys of a piano, all the white keys belong to the C major scale. If you start on C and proceed to play every white' key until the next C is reached, what is produced is the C major scale.

Playing any other major scale involves substituting one or more black keys for white keys to maintain the pattern of half-steps and whole-steps. This is a way to help visualize what notes are sharpened or flattened.

Sharp Keys

Now, lets look at all the major scales that contain sharps, excusing C major as the natural key:

C Major has no sharps or flats
G Major has 1 sharp:
- F#
D Major has 2 sharps:
- F#, C#
A Major has 3 sharps:
- F#, C#, G#
E Major has 4 sharps:
- F#, C#, G#, D#
B Major has 5 sharps:
- F#, C#, G#, D#, A#
F# Major has 6 sharps:
- F#, C#, G#, D#, A#, E#
C# Major has 7 sharps:
- F#, C#, G#, D#, A#, E#, B#

As you can see above, as is the case so many times in music, a pattern exists. In fact, there are two patterns we need to highlight:

  1. The order of the key signatures, C - G - D - A - E - B - F# - C#, are a distance of a fifth apart. This is the order of the Circle of Fifths.
  2. Each time we move through the Circle of Fifths an accidental is added to the sequence. This order is F# - C# - G# - D# - A# - E# - B#.

To memorize the order in which the sharps are added, the following phrase is helpful:

F ather Charlie G oes D own A nd E nds B attle

F# Father
C# Charlie
G# Goes
D# Down
A# And
E# Ends
B# Battle

A Perfect Fifth and the Seventh Degree

Here are a few patterns you may find helpful:

  1. The order in which the key signatures are added is a perfect fifth apart. The perfect fifth above F# is C#. The perfect fifth above C# is G#. etc.
  2. The last sharp in the sequence is the seventh degree of the key. Lets look at D major scale as an example. D - E - F# - G - A - B - C# - D has two sharps; F# and C# as its key signature. C# is the seventh degree of D major.
  3. When presented with a key signature, you can quickly determine the root note of the scale by raising the last sharp in the sequence by one half-step. For example, if you are given the key signature F#, C#, raising C# by one half-steps gives you a D, and this is indeed the key signature for D major.

Using the Circle of Fifths to Calculate Keys

To calculate the key of a given major scale, the first thing we need to do is determine the position of the key, relative to the starting point C major.

Once the position of the key signature is known within the Circle of Fifths, we can easily calculate the number of sharps associated with this key. For example:

D major is in the second position relative to the starting point, C major and has 2 sharps.

D Relative to C on the Circle of 5ths

Now that we understand the order, we need to determine which notes have been sharpened. Remembering the pattern above, the sharp notes are added in a specific sequence; F#; C#; G#; D#; A#; E#; and finally B#.

Continuing on with our example, we calculated that D major has 2 sharps. Understanding the order in which sharps are added, we can conclude that D major has F# and C# as its key signature.

Memorizing the Order of the Circle of Fifths

As a side note any sentence can be used to remember an order of letter names. If you are new to key signatures, you may use this
adapted Father Charlie sentence to remember the order for sharp keys as they fit in with the cycle of fifths:
C harlie G oes D own A nd E nds B attle F or C hild

Flat Keys

Now, lets look at all the major scales that contain flats, excusing C major as the natural key:

C Major has no sharps or flats
F Major has 1 flat:
- Bb
Bb Major has 2 flats:
- Bb, Eb
Eb Major has 3 flats:
- Bb, Eb, Ab
Ab Major has 4 flats:
- Bb, Eb, Ab, Db
Db Major has 5 flats:
- Bb, Eb, Ab, Db, Gb
Gb Major has 6 flats:
- Bb, Eb, Ab, Db, Gb, Cb
Cb Major has 7 flats:
- Bb, Eb, Ab, Db, Gb, Cb, Fb

There are two patterns we need to highlight:

  1. The order of the key signatures, C - F - Bb - Eb - Ab - Db - Gb - Cb, are a distance of a fourth apart. This is the order of the Circle of Fourths.
  2. Each time we move through the Circle of Fourths an accidental is added to the sequence. This order is Bb - E

To memorize the order in which the sharps are added, the following phrase is helpful:

B attle E nds A nd D own G oes C harlies F ather

Bb Battle
Eb Ends
Ab And
Db Down
Gb Goes
Cb Charlie's
Fb Father

Using the Circle of Fourths to Calculate Keys

As we did with the sharp keys, the first thing we need to do is determine the position of the key, relative to the starting point C major.

Once the position of the key signature is known within the Circle of Fourths, we can easily calculate the number of flats associated with this key. For example:

Bb major is in the second position relative to the starting point, C major and has 2 flats.

Bb Relative to C on the Circle of 4ths

Now that we understand the order, we need to determine which notes have been flattened. Remembering the pattern above, the flat notes are added in a specific sequence; Bb - Eb - Ab - Db - Gb - Cb and finally Fb.

Continuing on with our example, we calculated that Bb major has 2 flats. Understanding the order in which flats are added, we can conclude that Bb major has Bb and Eb as its key signature.

Reversing the Order

It is interesting to notice that the order in which the flats are added is in reverse order to that which the sharp keys are added.

Sharps Order F# C# G# D# A# E# B#
Sharps Reversed B# E# A# D# G# C# F#
Flats Order Bb Eb Ab Db Gb Cb Fb