The Rules of American Football

The Objective of the Game

Two teams of 11 players each try to advance an oval ball into the opponent's territory and carry it into their end zone. Whoever finishes the game with more points wins — the rest of the rulebook is, in practice, a set of rules about how the ball gets advanced and how points get scored along the way.

Unlike most other football codes, possession changes often and predictably: each team takes turns being the offense (the side holding the ball) and the defense (the side trying to stop it or take it away). This fast alternation, organized into short plays, is what gives American football its distinctive rhythm — stop, plan, action, stop again.

The Field and Its Dimensions

The field is 100 yards (about 91 meters) long between the two goal lines, plus a 10-yard end zone at each end where touchdowns are scored. End to end, the field measures 120 yards. It's 53.3 yards (about 48.8 meters) wide.

The field is marked yard by yard, with heavier lines every five yards and numbers showing the distance to the nearest goal line — which is why commentators talk about "the 20-yard line" or "the 35." These markers are essential for quickly reading where the ball is and how close a team is to scoring.

Game Length and the Clock

An NFL game has four 15-minute quarters, with a short break between the first and second, and between the third and fourth, plus a longer break — halftime — between the second and third quarters.

The clock stops frequently — after an incomplete pass, when a player steps out of bounds, on penalties, or when the offense calls a timeout — which is why 60 minutes of game time actually takes close to three hours to play. Additional stopping rules kick in during the last two minutes of each half, designed to keep the game competitive right up to the end.

If the score is tied after four quarters, the game goes to overtime, with its own rules about who gets the ball first and what counts as a game-ending score.

The Set of 4 Downs

Every offensive possession is broken into sets of four downsAn offensive team's attempt to advance the ball at least ten yards within four tries.. The offense must advance the ball at least ten yards within those four attempts to earn a new set of downs; succeed, and the count resets to "first down" for another cycle. Fail, and the ball typically goes to the other team.

The first three downs are usually spent probing the defense and building toward the needed distance. Fourth down is decision time: the team can go for the conversion, punt to flip field position, or attempt a field goal, depending on how close it is to the goal line.

Possession can also change before fourth down, through an interception or a fumbleA loss of ball control by the ball carrier before the play is ruled dead. recovered by the defense — which is why holding onto the ball is one of the most heavily drilled skills in the sport.

The Forward Pass

American football is one of the few major sports where the ball can be thrown forward to a teammate — a rule introduced only in 1906 that completely changed how the game is played today. Each play allows a single forward pass, usually thrown by the quarterbackThe player who leads the offense and receives the ball at the start of nearly every play., and only from behind the line of scrimmage (the imaginary line where the play begins).

A pass can be complete (caught by a teammate), incomplete (hits the ground, no change of possession), or intercepted (caught by an opposing player, instantly flipping possession). When the ball hits the ground uncaught, play stops automatically — unlike a run, where play continues until the ball carrier is tackled.

A commonly used variation is play actionA pass preceded by a fake handoff, meant to trick the defense., where the quarterback fakes a handoff before throwing, to trick the defense and buy an extra split second.

How Points Are Scored

The most valuable play is the touchdownThe highest single-play score, earned when the ball crosses into the opponent's end zone., worth six points, scored when a player on offense carries or catches the ball into the opponent's end zone. After every touchdown, the scoring team can attempt an extra point (a simple kick, worth one point) or a two-point conversion on another short play.

If the offense can't advance far enough for a touchdown, it can attempt a field goal — a kick through the goalposts at the back of the end zone, worth three points. Field goals are usually the logical choice when a team is too far out for a safe touchdown but close enough for a reliable kick.

There's also a rarer play: the safetyThe deepest defensive player, the last line of defense against long passes., which awards two points to the defense when it tackles an offensive player in that offense's own end zone. Uncommon as it is, a safety can completely change a game's momentum, since the scoring team also gets the ball back.

Offensive Positions

The offensive line — usually five very large players — has the often-thankless but essential job of protecting the quarterback and opening running lanes. Behind them, the running back carries the ball or blocks, and the wide receiversThe offensive player specialized in catching passes, usually lined up near the sideline. run pre-set routes to catch the quarterback's passes.

The tight end is something of a hybrid: solid enough to block like a lineman, fast enough to catch passes like a receiver. Many modern schemes use two or even three tight ends at once, precisely for that versatility.

All of these positions ultimately depend on the quarterback's decisions, made in a few seconds — pass, hand off, or run it himself.

Defensive Positions

The defensive line tries to stop the run and get to the quarterback before he can throw. Behind them, linebackers cover both inside runs and short passes, and are often considered the defense's brain.

Further back, in the secondary, cornerbacksThe defender responsible for directly covering opposing wide receivers on the outside. cover opposing wide receivers directly on the outside, while safeties are the last line of defense against deep passes. Sometimes the defense sends extra players after the quarterback in a blitzA defensive rush sending more players than usual after the quarterback., risking open space elsewhere in exchange for faster, heavier pressure.

Common Penalties

The penalties seen most often on TV are offside (a defensive player moves before the play starts), false start (an offensive player moves before the snap), holding (illegally grabbing or blocking an opponent with the hands), and pass interference (illegal contact with a receiver before the ball arrives).

Most penalties result in yards gained or lost by one of the teams, sometimes along with a replayed down or an automatic first down. A disciplined team with few penalties has a real edge — penalty yards add up quickly and can turn a promising set of downs into a failed one.

Special Teams

Special teams take the field at the game's transition moments: the kickoff at the start of a half or after a score, the punt (when the offense voluntarily gives up the ball to flip field position), and field goals.

Though they spend less time on the field than the offense and defense, special teams can decide a game — a long kickoff return or a missed field goal in the final seconds are the kind of moments fans remember long after the final whistle.