The length of the game is regulated according to the age and physical strength of the players. College basketball teams play two 20-minute halves, with a 15-minute rest between halves. If the score is tied at the end of the two halves, play continues for as many five-minute overtime periods as it takes for one team to break the tie. High school teams play four eight-minute periods, with a ten-minute intermission at halftime, plus three-minute overtime periods if needed. Boys under 13 years old play four six-minute quarters, with a ten-minute rest period at halftime. NBA games consist of four 12-minute periods with a 20-minute rest between halves. The tie-breaking overtime periods are five minutes long.