How many periods are in a regulation NFL game?

A regulation NFL game has four periods, commonly called quarters.

Each quarter lasts 15 minutes of game time, creating 60 minutes of scheduled playing time. The first and second quarters make up the first half, followed by halftime. The third and fourth quarters form the second half. Teams also change which end zone they defend after the first and third quarters.

The clock does not run continuously for 15 minutes because it stops for events such as incomplete passes, players going out of bounds, timeouts, certain penalties, scores, and the two-minute warning. As a result, an NFL game usually takes more than three hours in real time even though regulation contains only one hour on the game clock.

Overtime is separate from regulation. If the score is tied after the fourth quarter, the applicable overtime rules determine whether additional play is needed. This is why “four periods” remains the correct answer even when a game ultimately lasts longer. A common mix-up is counting halftime or overtime as an additional regulation period; neither is one of the four standard quarters.