<P> In American college basketball, there are two systems of timeouts used . In games that are not broadcast, each team is allowed four 75 - second and two 30 - second timeouts per regulation game . In games which are being broadcast, as of the 2015 - 16 season, each team is granted one 60 - second timeout and three 30 - second timeouts per game in addition to the media timeouts (at the first dead ball under 16, 12, 8 and 4 minutes remaining in each half). A maximum of three 30 - second timeouts may carry over into the second half . Any called timeout that occurs within the 30 seconds prior to a scheduled media timeout break automatically takes the place of the upcoming media timeout, with the only exception to this rule being the first called timeout of the second half . A timeout cannot be called by a coach when the ball is live . Previously, under NCAA rules in prior seasons, teams had a total of five timeouts, and timeouts superseding media timeouts were only used in the women's rules . </P> <P> High school basketball allots five timeouts per game, with three 60 - second and two 30 - second timeouts . In overtime games, each team is given one additional 60 - second timeout, and is allowed to carry over any unused timeouts from regulation or--if the case may be--previous overtimes . Media timeouts are typically reserved for televised state tournament games only . </P> <P> In the North American National Basketball Association, the rule on timeouts is more complex . Teams are allowed one 20 - second timeout per half, and six regular timeouts, of one minute in length over the course of the entire game . During a 20 - second timeout, only one player may be substituted . During a regular timeout, there is no limit on substitutions . In the first and third quarter, there must be two 100 - second timeouts . If neither team has taken a timeout prior to 6: 00 of the first or third period, the Official Scorer must take it at the first dead ball and charge it to the home team . If no subsequent timeouts are taken prior to 3: 00, the Official Scorer must take it and charge it to the team not previously charged . In the second and fourth quarter, there must be three 100 - second timeouts . If neither team has taken a timeout prior to 9: 00 of the second or fourth period, a mandatory timeout is called by the Official Scorer and charged to neither team . If there are no subsequent timeouts taken prior to 6: 00, the Official Scorer must take it at the first dead ball and charge it to the home team . If no subsequent timeouts are taken prior to 3: 00, the Official Scorer must take it and charge it to the team not previously charged . In the fourth quarter, each team is limited to a maximum of three timeouts and if a team has two or three full timeouts remaining when the fourth period reaches the 2: 00 mark, one of the timeouts will be changed to a 20 - second timeout and it will retain one full timeout . In overtime periods, each team shall be allowed two 60 - second timeouts and one 20 - second timeout . If a team has two full timeouts remaining when the overtime period reaches the 2: 00 mark, one of the timeouts will be changed to a 20 - second timeout . </P> <P> The Official Scorer notifies a team when it has been charged with a mandatory timeout . Additional timeouts in a period, beyond those that are mandatory, are for 60 seconds . </P>

How long is an nba 20 second timeout