In 4/4 time, also known as common time, the top number indicates that there are four beats in each measure, and the bottom number indicates that a quarter note receives one beat. Therefore, in 4/4 time, the quarter note gets the beat. This means that each quarter note lasts for one beat, and other note durations are relative to the quarter note. For example, a half note lasts for two beats, an eighth note lasts for half a beat, and so on.
