Key Signatures in Music Theory and Notation

Key signatures play an important role when it comes to reading and writing music; they indicate the key of the song by telling you how many sharps or flats there are. In this tutorial we’ll look at different key signatures and I’ll explain how to read them.


Every key has it’s own ‘signature’ and is determined by the number of flats or sharps it contains. The key signature is found just to the right of the clef and it contains flats or sharps, the number of which determines what key the song is in.

In the example below there are two sharps: F# and C#. For the whole song all the F’s and all the C’s are sharped unless a new key signature is introduced or if there’s an accidental.

Key Signature in D major/b minor

An accidental is a sharp, flat, or natural sign that is not in the key signature but appears next to a note. Accidentals only last until the end of the measure or through tied notes across a measure.

In the key signature sharps and flats always appear in the same order which is directly related to the circle of fifths.

Order of sharps: F C G D A E B
Fat Cats Gargle Daily After Eating Breakfast. Yea I know it doesn’t really make sense, but it really helps you remember the order of sharps.

Order of flats: B E A D G C F
I never really had a saying for this one, I just remember Bead GCF. But I suppose you could use Before Eating At Dennys Guys Can Fart.

It’s a good idea to learn all of your major and minor scales. That way when you see a key signature with two sharps (like the one above) you will know that the song is in the key of D major. The essentials of learning music theory start with understanding all the different symbols.