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Key Signature Identification

Key signatures indicates accidentals that they will be used in the score, and they indicate the name of the key. Each key signatures indicates a name of a specific key.

Here, we will learn how to find the name of the key from a specific key signature, and how to find the key signature from a specific key name (scale name).

You had to know the flats order and the sharps order:

The order of flats is: B♭ E♭ A♭ D♭ G♭ C♭ F♭
The order of sharps is: F♯ C♯ G♯ D♯ A♯ E♯ B♯

Neutral key signature

A neutral key signature means that the key is C Major

Finding key names from key signatures with flats

How to find key names from key signatures with flats?
Finding key names from key signatures with flats

Method #1


The last flat (♭) is always the degree IV of the major scale.

Example with 6 ♭:

Key signature identification with flats example 1

With a 6♭ key signature, the last flat is C♭ (B♭ E♭ A♭ D♭ G♭ C♭ F♭) and C♭ is the degree IV, so degree I is G♭.
Conclusion: A key signature with 6 flats (6♭) indicates the key of G♭ Major

Example with 1 ♭:

Key signature identification with flats example 2

With a 1♭ key signature, the last flat is B♭ (B♭ E♭ A♭ D♭ G♭ C♭ F♭) and B♭ is the degree IV, so degree I is F.
Conclusion: A key signature with 1 flat (1♭) indicates the key of F Major

Method #2


The second to last flat (♭) is always the degree I of the major scale.

Key signature identification with flats example 3

With a 6♭ key signature, the second to last flat is G♭ (B♭ E♭ A♭ D♭ G♭ C♭ F♭) and G♭ is the degree I.
Conclusion: A key signature with 6 flats (6♭) indicates the key of G♭ Major

Disadvantage: It doesn't work with only 1 flat in the key signature (F Major).

Finding key names from key signatures with sharps

How to find key names from key signatures with sharps?
Finding key names from key signatures with sharps

Method #1


The last sharp (♯) is always the degree VII of the major scale.

Example with 6 ♯:

Key signature identification with sharps example 1

With a 6♯ key signature, the last sharp is E♯ (F♯ C♯ G♯ D♯ A♯ E♯ B♯) and E♯ is the degree VII, so degree I is F♯.
Conclusion: A key signature with 6 sharps (6♯) indicates the key of F♯ Major

Method #2


Adding a half step united states of america (semitone united kingdom) to the last sharp (♯) give the degree I of the major scale.

Example with 6 ♯:

Key signature identification with sharps example 2

With a 6♯ key signature, the last sharp is E♯ (F♯ C♯ G♯ D♯ A♯ E♯ B♯) and adding a half step united states of america (semitone united kingdom) to E♯ give the degree I: F♯.
Conclusion: A key signature with 6 sharps (6♯) indicates the key of F♯ Major

Finding key signatures from key names


- Major scales with the word flat (♭) have key signatures with flats (♭)
- Major scales without the word flat (♭) have key signatures with sharps (♯)


For example:

- E♭ Major, A♭ Major, D♭ Major have key signatures with flats.
- D Major, G Major, F♯ Major have key signatures with sharps.

Finding the key signature of A♭ Major

A♭ Major contains the word flat, so key signature of A♭ Major will have flats (♭).

The second to last flat (♭) is always the degree I of the scale.

Finding key signature of A flat major

So if A♭ is the second to last flat, so D♭ is the last.

Conclusion: The key signature of A♭ Major contains 4 flats (4♭)

Finding the key signature of B Major

Major scales without the word flat (♭) have key signatures with sharps (♯), so key signature of B Major will have sharps (♯)

The last sharp (♯) is always the degree VII (leading tone united states of america / leading note united kingdom) of the scale.

The leading tone united states of america (leading note united kingdom) of B Major is A♯.

Finding key signature of B major

Conclusion: The key signature of B Major contains 5 sharps (5♯)

Finding key signatures of minor scales

To find key signatures of minor scales, you must find the relative major key of the minor scale.


For example, if you want to find the key signature of F minor you must find its relative major key:

The relative major key is always a minor third above the minor key, so the relative major key of F minor is A♭ Major, and next you must find the key signature of A♭ Major (4♭).

Finding key names and key signatures with the circle of fifths


You can find all key names and all key signatures with the the circle of fifths:

circle of fifths

For example, with the the circle of fifths, it is clear that A♭ Major and F minor have a key signature with 4 flats (♭)


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