American football
Football games last for a total of 60 minutes in professional and college play and are divided into two-halves of 30 minutes and four-quarters of 15 minutes. High school football games are 48 minutes in length with two-halves of 24 minutes and four-quarters of 12 minutes. The two-halves are separated by a halftime period, and the first and third quarters are also followed by a short break. Prior to the start of the game, the referee and team captains for each team meet at midfield for a coin toss. The visiting team is allowed to call 'heads' or 'tails'; the winner of the toss is allowed to decide between choosing whether to receive or kick off the ball or choosing which goal they want to defend, but they can also defer their choice until the second half. The losing team, unless the winning team decides to defer, is allowed to choose the option the winning team did not select, and receives the option to receive, kick, or select a goal to defend to begin the second half. Most teams choose to receive or defer, because choosing to kick the ball to start the game would allow the other team to choose which goal to defend. Teams switch goals following the first and third quarters. If a down is in progress when a quarter ends, play continues until the down is completed.
Laws of Australian rules football
The length of a game of Australian Football can vary from league to league, but is generally around 15 to 25 minutes per quarter. In the AFL, each quarter runs for 20 minutes plus time on – which makes up for time occupied in stoppages, such as when the ball goes out of bounds, injuries, goals (or behinds) being kicked, or when the umpire is setting the angle of a free kick on goal. A typical AFL quarter might run from 27 to 33 minutes, but may be even longer if, for instance, injuries cause delays. AFL breaks after the first and third quarters are 6 minutes, with a 20-minute break at halftime. Thus, a match with quarters averaging 30 minutes would last about two and a half hours.