Also known as the circle of fourths, this is a easy guide info using the circle of fifths to find out the key we are playing in.
Starting at the top of the chart with c major/ a minor which has no sharp notes. (Remember the outter notes are major and the inner notes are relative minor. They share the same sharp/flat notes: E major is the same as c#minor, A flat major is the same as F minor, and so on.
A – B – C – D – E – F – G
If you count a fifth from C major, you will get Gmajor. If you count a fifth above G major you get D Major. Follow this process to build your circle of fifths.
By following the circle of fifths to the right you can see how many sharp are in each key (1 sharp added per fifth raised).
By following the circle of fifths to the left you can see how many flats are in each key (1 flat added per fifth raised).
This image is pretty useful as it shows you how many sharps/flats are in each key. For example in G we see it has 1 sharp. This sharp would be an F. If we were to play in A major we would have 3 sharps; which would be G – C – F
If you were to play in DFlat major you would have 7 sharp notes: F – C – G – D – A – E – B
A useful way to remember this is beadgcf (bead greatest common factor) which is the order of sharps within a key.
To remember it as fcgdaeb; which is the order of flats, we can use – father Charles goes down and ends battle.
When you add a new sharp/flat, you need to keep the ones which appear before it in this order (unless you are altering the major scale).
If you were in Emajor; which has 4 sharps, you would use F# – C# – G# – D#
If you were to play in A flat major; which has 4 flats, you would use Bflat – E flat – A flat – D flat