Association football

====90-minute ordinary time====
A standard adult football match consists of two halves of 45 minutes each. Each half runs continuously, meaning that the clock is not stopped when the ball is out of play. There is usually a 15-minute half-time break between halves. The end of the match is known as full-time.<ref name="rule7.2"/> The referee is the official timekeeper for the match, and may make an allowance for time lost through substitutions, injured players requiring attention, or other stoppages. This added time is called "additional time" in FIFA documents,<ref>{{cite web|url=https://www.fifa.com/mm/document/worldfootball/clubfootball/01/37/04/23/interpretation_law07_en.pdf|archive-url=https://web.archive.org/web/20120721055324/http://www.fifa.com/mm/document/worldfootball/clubfootball/01/37/04/23/interpretation_law07_en.pdf|archive-date=21 July 2012|title=Interpretation of the Laws of the Game&nbsp;– Law 07|url-status=dead|publisher=FIFA}}</ref><ref>{{cite web|url=https://www.fifa.com/mm/document/afdeveloping/refereeing/law_7_the_duration_of_the_match_en_47401.pdf|archive-url=https://web.archive.org/web/20110304214713/http://www.fifa.com/mm/document/afdeveloping/refereeing/law_7_the_duration_of_the_match_en_47401.pdf|url-status=dead|archive-date=4 March 2011|title=Law 7 – The Duration of the Match|publisher=FIFA}}</ref> but is most commonly referred to as ''stoppage time'' or ''injury time'', while ''lost time'' can also be used as a synonym. The duration of stoppage time is at the sole discretion of the referee. Stoppage time does not fully compensate for the time in which the ball is [[Ball in and out of play|out of play]], and a 90-minute game typically involves about an hour of "effective playing time".<ref>{{cite news|title=Football reforms: Scrapping 45-minute half to be debated at Ifab|url=https://www.bbc.co.uk/sport/football/40311889|access-date=7 March 2018|work=BBC Sport|date=18 June 2017|archive-date=22 March 2018|archive-url=https://web.archive.org/web/20180322022354/http://www.bbc.co.uk/sport/football/40311889|url-status=live}}</ref><ref>[https://fivethirtyeight.com/features/world-cup-stoppage-time-is-wildly-inaccurate/amp/ We Timed Every Game. World Cup Stoppage Time Is Wildly Inaccurate] {{Webarchive|url=https://web.archive.org/web/20201112201239/https://fivethirtyeight.com/features/world-cup-stoppage-time-is-wildly-inaccurate/amp/ |date=12 November 2020 }}, David Bunnell, FiveThirtyEight, 27 June 2018</ref> The referee alone signals the end of the match. In matches where a fourth official is appointed, towards the end of the half, the referee signals how many minutes of stoppage time they intend to add. The fourth official then informs the players and spectators by holding up a board showing this number. The signalled stoppage time may be further extended by the referee.<ref name="rule7.2">{{cite web|url=https://www.fifa.com/flash/lotg/football/en/Laws7_02.htm |publisher=FIFA |title=Laws of the game (Law 7.2 – The duration of the match) |access-date=24 September 2007 |archive-url=https://web.archive.org/web/20071011144952/http://fifa.com/flash/lotg/football/en/Laws7_02.htm |archive-date=11 October 2007 |url-status=dead }}</ref> Added time was introduced because of an incident which happened in 1891 during a match between [[Stoke City F.C.|Stoke]] and [[Aston Villa F.C.|Aston Villa]]. Trailing 1–0 with two minutes remaining, Stoke were awarded a penalty kick. Villa's goalkeeper deliberately kicked the ball out of play; by the time it was recovered, the clock had run out and the game was over, leaving Stoke unable to attempt the penalty.<ref>[[The Sunday Times]] ''Illustrated History of Football'' Reed International Books Limited 1996. p. 11 {{ISBN|1-85613-341-9}}</ref> The same law also states that the duration of either half is extended until a penalty kick to be taken or retaken is completed; thus, no game can end with an uncompleted penalty.<ref>{{cite web|url=https://www.fifa.com/flash/lotg/football/en/Laws7_03.htm |archive-url=https://web.archive.org/web/20071019042952/http://www.fifa.com/flash/lotg/football/en/Laws7_03.htm |archive-date=19 October 2007 |publisher=FIFA |title=Laws of the game (Law 7.3 – The duration of the match) |access-date=3 March 2010 |url-status=dead }}</ref>