Count out the bars of the intro, if there is one. Not all rap songs have a vocal intro, but if so, it is likely to be eight bars long. If there is no vocal intro, count out the instrumental beats. Most rap song beats are created using 4/4 time, meaning that there are four beats per measure. A bar is made up of every four intervals of notes. The instrumental will likely be eight bars long. For example: count 1,2,3,4 then 1,2,3,4 and so on right up until the first verse starts. Every four counts constitutes a bar.
Count the bars of the first verse. It will likely be 16 bars long.
Count the bars of the first hook, also known as the chorus. It will likely be eight bars long.
Count the bars of the second verse. It will be likely be 16 bars long.
Count bars of the second hook. It will likely be eight bars long.
Count the bars of the third verse. It will likely be 16 bars long.
Count the bars of the third hook. It will likely be eight bars long.
Count out the outro. It will be a minimum of 16 bars, but could contain as many as 32 or more bars. Sometimes rappers will "talk" their way out of the song.
Add up the total number of bars to determine the total number in the song.