How much time is in each quarter of an American football game?
Comparison of American football and rugby union
A rugby union game is divided into two halves of 40 minutes (or shorter for lower-grade games, and breaks given halfway through each half if playing conditions are considered to be extreme) separated by a half time period of up to 15 minutes in an international match. Most notably, a rugby union game will continue after the scheduled end of a half (half-time or full-time) until the ball becomes dead - any occurrence that would have play restart with a scrum or lineout, or when a team scores. This has led to some "nail-biting" finishes where teams losing by only a small margin work their way towards scoring, and games can go on several minutes over time. Something similar can occur at the end of either half in American football, though usually for only a few seconds of additional time, because a play that begins before the half expires continues until the ball is dead regardless of whether there is any time left on the clock. In both sports, the clock is also stopped during substitutions and for injuries, so the referee does not need to add stoppage time as is done in soccer/Association football. American football games are made up of four quarters of 15 minutes each (less at the high school and youth levels), but the clock stops and starts according to specific rules, so that a 15-minute quarter lasts much longer.
List of gridiron football rules
The methods of scoring are:Resumption of play following a score is conducted under procedures which vary with the type of score.The game consists of two 30-minute halves, each of which is divided into two 15-minute quarters. The clock counts down from 15:00 in each quarter. Timing rules change when there are three minutes remaining in a half.
A 2-minute interval occurs after the end of each quarter (15 minutes at halftime, except 30 minutes in Grey Cup), and the two teams then change goals.