In or , an interception occurs when a forward pass is caught by a player of the opposing defensive team. This leads to an immediate change of possession during the play: the defender who caught the ball immediately attempts to move the ball as far towards the opposing end zone as possible. Following the stoppage of play, if the interceptor retained possession of the ball, his team takes over possession at the spot where he was downed.
Interceptions are predominantly made by the secondary or (on some occasions) the linebackers, who are usually closest to the quarterback's intended targets, the wide receivers, running backs, and tight ends. Less frequently, a may get an interception from a tipped ball, a near sack, a shovel pass, or a screen pass, but are more likely to force a fumble than get an interception. As soon as a pass is intercepted, everyone on the defense immediately acts as , helping the person with the interception get as much yardage as possible and perhaps a touchdown (commonly called a "pick six"); at the same time, everyone on the offense becomes the defense and may attempt to the ball-carrier. If the interception occurs on an extra point attempt, rather than an ordinary play from scrimmage, a potential return of the interception to the other end zone is sometimes called a "pick two" as it would be a defensive two point conversion rather than a touchdown. For example, on December 4, 2016, the Kansas City Chiefs strong safety Eric Berry scored the game winning points via a pick two in a 29–28 victory over the Atlanta Falcons. Berry also achieved an ordinary pick six earlier in the same game.
If the intercepting team can run out the clock, the intercepting player may down the ball immediately and not attempt to gain any yardage. This eliminates the chance of a fumble that could be recovered by the other team. There are also player safety implications: when the ball is turned over, the play is now suddenly and unexpectedly moving in the opposite direction. All of the players on offense are instantly susceptible to unexpected blocks, even if not attempting to stop the ball carrier; a hard and unseen block can result in severe injuries. Additionally, offensive players, particularly the quarterback, are often inexperienced tacklers and are at risk of injuring themselves while tackling the ball carrier.
Only the interception of a forward pass is recorded statistically as an interception, for both the passer and the intercepting player. If a receiver fails to catch the ball and bobbles or tips it before it is intercepted, even if his action was entirely responsible for the interception, it is always recorded as an interception thrown by the passer. The interception of a lateral pass is recorded as a fumble by the passer.