How long overtime will last for Senators-Hurricanes in NHL playoff rules originally appeared on The Sporting News. Add The Sporting News as a Preferred Source by clicking here.It looked like the night in Carolina was over.Instead, Hurricanes and Senators are set up for a long night of overtime hockey.Carolina seemed to win the game in the first OT, but the goal was called off.Then there was a penalty shot, but Ottawa goalie Linus Ullmark denied it.There had been 20 minutes of five-on-five hockey in the OT period, but it ended up with no goals.And so on they go.MORE: The confusing goal that didn't count for the HurricanesHow long is NHL playoff overtime?NHL playoff games play 5-on-5 hockey until the game is over.Each overtime period lasts 20 minutes, like a regulation period.But at the end of 20 minutes, it's like the end of a period. Teams get a break, the ice gets spruced up, and then they come out with switched benches.The game goes until someone scores the winning goal.MORE: Sabres provide Buffalo a magical night 5,472 days in the makingWhat is longest NHL playoff overtime game?The longest game was in in 1936 when the Red Wings beat the Montreal Maroons in six overtime periods which featured 116 minutes and 30 seconds of extra game time.The most recent marathon game was in 2023 when the Florida Panthers beat the Hurricanes in four overtimes.More NHL news:'Better Days,' Buffalo and a Sabres team uniting a cityPorter Martone matches some 1929 NHL history for Flyers