Editing Ice hockey (section)

===Periods and overtime===
A professional ice hockey game consists of three periods of twenty minutes, the clock running only when the puck is in play.{{sfn|National Hockey League|2024|p=118}} There is a rest period between the three periods.{{sfn|National Hockey League|2024|p=118}} The teams change ends after each period of play, including overtime. Recreational leagues and children's leagues often play shorter games, generally with three shorter periods of play.

[[File:American Hockey League ERI 5695 (5528600480).jpg|thumb|Scoreboard for a hockey game during the fourth period. If a game is tied at the end of the third period, several leagues and tournaments have teams play additional [[sudden death (sport)|sudden death]] overtime periods.]]

If a tie occurs in tournament play, as well as in the NHL playoffs, North Americans favour ''sudden death [[Overtime (ice hockey)|overtime]]'', in which the teams continue to play twenty-minute periods until a goal is scored. Up until the 1999–2000 season, regular-season NHL games were settled with a single five-minute sudden death period with five players (plus a goalie) per side, with both teams awarded one point in the standings in the event of a tie. With a goal, the winning team would be awarded two points and the losing team none (just as if they had lost in regulation). The total elapsed time from when the puck first drops, is about 2 hours and 20 minutes for a 60-minute game.

From the 1999–2000 until the 2003–04 seasons, the National Hockey League decided ties by playing a single five-minute sudden-death overtime period with each team having four skaters per side (plus the goalie). In the event of a tie, each team would still receive one point in the standings but in the event of a victory the winning team would be awarded two points in the standings and the losing team one point. The idea was to discourage teams from playing for a tie, since previously some teams might have preferred a tie and 1 point to risking a loss and zero points. The exception to this rule is if a team opts to pull their goalie in exchange for an extra skater during overtime and is subsequently scored upon (an ''empty net'' goal), in which case the losing team receives no points for the overtime loss. Since the 2015–16 season, the single five-minute sudden-death overtime session involves three skaters on each side. Since three skaters must always be on the ice in an NHL game, the consequences of penalties are slightly different from those during regulation play; any penalty during overtime that would result in a team losing a skater during regulation instead causes the other side to add a skater. Once the penalized team's penalty ends, the penalized skater exits the penalty box and the teams continue at 4-on-4 until the next stoppage of play, at which point the teams return to three skaters per side.<ref>{{cite web|url=http://www.nhl.com/nhl/en/v3/ext/rules/2015-2016-Interactive-rulebook.pdf|title=National Hockey League Official Rules 2015–2016|publisher=National Hockey League|year=2015|archive-url=https://web.archive.org/web/20151025215742/http://www.nhl.com/nhl/en/v3/ext/rules/2015-2016-Interactive-rulebook.pdf|archive-date=October 25, 2015|url-status=dead}}</ref>
[[File:Peter Mueller shootout goal.jpg|thumb|Several leagues and tournaments have implemented the [[shootout (hockey)|shootout]] as a means to determine a winner, if the game remains tied after an extra overtime period.]]
International play and several North American professional leagues, including the NHL (in the regular season), now use an overtime period identical to that from 1999–2000 to 2003–04 followed by a [[Shootout (hockey)|penalty shootout]]. If the score remains tied after an extra overtime period, the subsequent shootout consists of three players from each team taking penalty shots. After these six total shots, the team with the most goals is awarded the victory. If the score is still tied, the shootout then proceeds to ''[[Sudden death (sport)|sudden death]]''. Regardless of the number of goals scored by either team during the shootout, the final score recorded will award the winning team one more goal than the score at the end of regulation time. In the NHL if a game is decided in overtime or by a shootout the winning team is awarded two points in the standings and the losing team is awarded one point. Ties no longer occur in the NHL.

Overtime in the NHL playoffs differs from the regular season. In the playoffs there are no shootouts. If a game is tied after regulation, then a 20-minute period of 5-on-5 sudden-death overtime will be added. If the game is still tied after the overtime, another period is added until a team scores, which wins the match. Since 2019, the IIHF World Championships and the gold medal game in the Olympics use the same format, but in a 3-on-3 format.