Along with scoring a touchdown or successfully kicking a field goal, another way for teams to score in football is through a safety. While safeties are much less common than touchdowns and field goals, it's important to know how they can change the outcome of a game.
A safety is worth two points in football. On very rare occasions a safety may be worth 1 point if it happens during an extra point or two-point conversion. Safeties are the least common and least rewarding method of scoring. A safety can happen in a few different situations, though it is always the result of a player causing a dead ball within his own end zone.
Most commonly, a safety occurs when the ball carrier is tackled or goes out of bounds in their own end zone after carrying the ball into the end zone. If the line of scrimmage is on a team's own one-yard line, and the quarterback is sacked in the end zone, a safety occurs. The offense committing a foul inside their own end zone can also result in a safety. Additionally, if the ball is fumbled out of bounds through a team's own end zone as a result of their own actions, this will be ruled a safety.
After a safety occurs, the ball is kicked off from the 20 yard line to the same team that scored the safety.
There is a very rare circumstance in which a safety can be worth only one point in a football game. This situation is so rare that it has never actually happened in an NFL game and has only occurred a few times in college football. For this to happen, a team would have to make a critical error following an extra point or two point conversion attempt.
A one-point safety for the offense can occur if the defense blocks the kick or otherwise gains possession of the ball on an extra point or two point conversion attempt and is then tackled in their own endzone. This would result in the offense receiving one point for the safety.
A one-point safety for the defense can happen if the offense has their kick blocked or loses possession of the ball, only to recover it and be tackled 85 yards or more backwards within their own endzone. This is extremely unlikely, but it would cause the defense to receive one point for the safety.
Remember not to confuse a touchback with a safety. If the offense's pass is intercepted or fumble recovered within a defense's own end zone and they are then tackled, it will be ruled a touchback. Apart from one nearly impossible situation, safeties can only occur when the offense has and maintains possession of the ball.