At the beginning of each piece of music, after the treble clef, is the time signature.
The time signature indicates the number of beats per bar (the top number) and the type of note receiving one beat (the bottom number).
Thus in * time there must be the equivalent of 4 quarter note beats per bar, e.g.:
* is the most common time signature and is sometimes represented by this symbol called common time.
Most Rock/Pop songs are in * time.
Some other common time signatures are ^, % and ). These are demonstrated in the following examples.
^ indicates 3 quarter note beats per bar, e.g.:
% indicates 2 quarter note beats per bar, e.g.:
) time indicates 2 dotted quarter note beats per bar, which can be divided into two groups of eighth notes as such: