Time Signatures

The top number in a time signature represents how many beats there are per bar.

If the top number is two then there must be two beats in a bar,
If the top number is three then there must be three beats in a bar,
If the top number is four, there must be four beats in a bar, and so on.

The bottom number tells us what kind of beat to count. For example, we might be counting crotchet beats, or minim beats or quaver beats. Here are all the bottom numbers in a time signature and their corresponding note values:

1 = Semibreve / Whole note
2 = Minim / Half note
4 = Crotchet / Quarter note
8 = Quaver / Eighth note
16 = Semiquaver / Sixteenth note

This is best explained with some examples:

The time signature 2/4 below, there should be two crotchet beats in each bar:

The top number tells us how many beats per bar (two in this case) and the bottom number tells us what kind of beat (crotchet beats in this case).

The number four is used because four crotchet beats are equal to one semibreve. If the bottom number in the time signature was a two then it would represent minim beats because two minim beats are equal to one semibreve.
The time signature 3/4 means there should be three crotchet beats in a bar:

Again, the top number tells us how many beats per bar (three in this case) and the bottom number tells us what kind of beat (crotchet beats as it’s a number four).
The time signature 4/4 means there are four crotchet beats in a bar:

The top number tells us how many beats per bar (four in this case) and the bottom number tells us what kind of beat (crotchet beats as it’s a number four which represents crotchets).
Another time signature you might see is one that looks like the letter C. This stands for common time and is exactly the same as 4/4:

But we don’t only have to use only crotchets if the bottom number in the time signature is a four. We can use longer or shorter notes too. The only rule is that they have to equal the number of beats in the time signature. For example, any of these are correct:

Just remember that every single bar should always add up to the correct number of beats indicated in the time signature.