A key signature will appear at the beginning of a piece of sheet music. This will tell you if sharps and flats will be played in the piece or if no sharps and flats will be played. If you don't see any sharps or flats at the beginning of the piece then this is normally referred to as open key or C major. Sharps and flats can be written in various bars throughout the piece and these are known as accidentals and will last for the bars duration only.



Sharps and flats at the beginning of a piece can also indicate which key the piece is written in although there are other elements of the piece that also determine this because major and minor keys can share the same key signature, for example C major and A minor share the same key signature, that is, no sharps or flats, also G major and E minor share the same key signature of one sharp, (F Sharp). These similarities are known as relatives. So C majors relative minor is A minor. They are relatives because they share the same key signature.

Since most people start to learn in major keys, we will use examples in major keys only. At the beginning of a piece of music, to the right of the treble clef and the bass clef is where you will see sharps and flats.

One sharp means all occurrences of F are sharp and the key is G major

Two sharps = F sharp and C sharp and the key is D major

Three sharps = F sharp, C sharp and G sharp and the key is A major

Four sharps = F sharp, C sharp, G sharp and D sharp and the key is E major

Five sharps = F sharp, C sharp, G sharp, D sharp and A sharp and the key is B major

Six sharps = F sharp, C sharp, G sharp, D sharp, A sharp and E sharp and the key is F sharp major

Seven sharps = F sharp, C sharp, G sharp, D sharp, A sharp, E sharp and B sharp and the key is C sharp major

One flat means all occurrences of B are flat and the key is F major

Two flats = B flat and E flat and the key is B flat major

Three flats = B flat, E flat and A flat and the key is E flat major

Four flats = B flat, E flat, A flat and D flat and the key is A flat major

Five flats = B flat, E flat, A flat, D flat and G flat and the key is D flat major

Six flats = B flat, E flat, A flat, D flat, G flat and C flat and the key is G flat major

Seven flats = B flat, E flat, A flat, D flat, G flat, C flat and F flat and the key is C flat major

No flats or sharps indicates the key of C major

A good way to learn all these keys is to use a method, which I call the rule of seven. By adding the amount of sharps a key has to the amount of flats a key has, you should always end up with seven. That means if you memorise either the sharps keys or the flat keys you can work out the other by creating a relationship. We create the relationship using the letters, for example, B major and B flat major. B major has five sharps B flat major has two flats 5+2=7. Lets try E major and E flat, once you know that E flat has three flats you can work out how many sharps are in E major. So if E flat has three flats then E major must have four sharps 3+4=7

The exception to this rule is C flat major and C sharp major, make sure to relate both these keys with C major.