Time signature

In the stave above there are two 4s. This combination is known as the 'Time signature' of the music.

The top number

The top '4' tells us there are four beats in each bar. We could put 3 or 5 or any number we can think of, but typically this number is a 2, 3 or 4.

We refer to the time signature as 4/4(four-four) or 3/4(three-four) where the top number comes first.

Here are some more examples:-

3 beats per bar	2 beats per bar	5 beats per bar
Each beat is a crotchet
Three-four time	Two-four time	Five-four time

The bottom number

The bottom '4': it says that these beats are crotchets.

If the number were a '2' then these beats would be minims. Similiarly, if it were '8' then the beats would be quavers.

2, 4 and 8 are the only numbers normally encountered.

3 beats per bar	3 beats per bar	3 beats per bar
Each beat is a minim	Each beat is a crotchet	Each beat is a quaver
Three-two time	Three-four time	Three-eight time

Special time signatures

There are two time signatures that are not in this format:

4 beats per bar	2 beats per bar
Each beat is a crotchet	Each beat is a minim
The same as 4/4 also known as common time	The same as 2/2 also known as Alla Breve

There are some special considerations with Compound time which are dealt with separately.