How many periods are in a regulation NHL game?

A regulation NHL game has three periods. Each period lasts 20 minutes of playing time, for 60 minutes in regulation.

The clock stops whenever play is interrupted, so a 60-minute game usually takes considerably longer in real time. Teams change ends after each period, and intermissions separate the three periods. The format helps give players recovery time while ensuring both teams attack each end of the rink under comparable conditions.

If the score is tied after the three regulation periods, the game is not over. In the NHL regular season, teams play a five-minute sudden-death overtime with three skaters and a goaltender per side, followed by a shootout if necessary. Playoff games use successive 20-minute sudden-death overtime periods instead, with teams skating five-on-five.

The three-period structure is also common in other levels of ice hockey, although youth, recreational, and tournament games may use shorter periods. A common mistake is counting overtime as a fourth regulation period: overtime is an additional phase, not part of the regulation total.