For example, this key signature indicates every F# in the piece should be sharped, regardless of the octave. |
C Major Scale |
C Major Key Signature |
In G Major, there is one sharp (F#). So the key signature is F#.
G Major Scale |
G Major Key Signature |
In F Major, there is one flat (B♭). So the key signature is B♭.
Purposes of a key signature:
- It indicates the key of the piece.
- It reduces the need for including sharps, flats and naturals with every note.
To work out the key of a piece of music:
- Look at the signature.
- Look at the last note - often (but not always) this will be the key note.