Basic rules
Never watched a game? Start here. These few pages explain the whole idea of football, step by step, with little animated plays.
The idea of the game
Two teams of eleven players meet on a long field. The team with the ball, called the offense, tries to carry or throw it into the end zone at the far end. The other team, the defense, tries to stop it. When a play ends, the two teams line up again and play the next one. At the end of the game, the team with more points wins.
Everything else on this site is built from that idea. Positions tell you who does what, the terms explain the words, and the animated plays show how it looks on the field.
The field
The field is a rectangle 100 yards long between the two goal lines, plus an end zone ten yards deep at each end. It is 53⅓ yards (160 feet) wide. Lines cross the field every 5 yards, and the numbers count up to 50 in the middle and back down again, so you always know how far the ball is from the goal.
Small marks called hash marks run up the field near the middle. The ball is placed between them at the start of each play, depending on where the last play ended. The long edges are the sidelines. A player who touches a sideline or the end line is out of bounds, and the play stops. Teams attack in opposite directions and switch ends after each quarter.
The ball
The football is oval with pointed ends, about 11 inches long and a little under a pound. Laces run along the top. They give the quarterback something to grip so he can throw a tight spiral that flies straight. Players can carry it, throw it, kick it and hand it from one to another. They cannot throw it forward more than once on a play, and only from behind the line of scrimmage.
How long is a game?
A game is four quarters of 15 minutes, so 60 minutes of playing time. After the second quarter there is a halftime break of about 12 minutes, and the teams switch ends. The clock stops after incomplete passes, when a runner goes out of bounds, after scores and during timeouts, so a game takes about three hours to watch in real life.
If the score is level after four quarters, the teams play overtime.
More: quarters, timeouts and overtime.
Offense, defense and special teams
A team has about 50 players on its game-day squad, but only 11 are on the field at a time. They come in three groups, called units.
The offense has the ball. Its job is to move the ball forward and score. It has a quarterback who passes and hands off, running backs, receivers and a line of five blockers. The defense tries to stop it with linemen, linebackers and defensive backs. Special teams come on for kicks: kickoffs, punts and field goals. They include the kicker, the punter and the long snapper. Whenever the ball changes hands, the units swap: the old offense leaves the field and the old defense comes on as the new offense.
Meet every player on the positions page.
Moving the ball: downs
The offense has four tries, called downs, to move the ball ten yards. If it makes it, it earns a first down: a fresh set of four tries. If it fails on fourth down, the other team takes over where the ball is. That is why teams usually kick on fourth down.
A single play starts when the center snaps the ball to the quarterback. It ends when the ball carrier is tackled or goes out of bounds, when a pass hits the ground (an incomplete pass), or when someone scores.
Drives
The whole stretch where one team keeps the ball is called a drive. A drive ends in a score, a punt, a turnover, or the end of a half. Most points come from long drives that move steadily down the field.
Scoring
There are five ways to score. A touchdown is the big one: six points for getting the ball into the end zone. After a touchdown the team can add one point with a kick or two points with a single play from the 2-yard line. A field goal, a kick through the uprights, is worth three points. A safety, which the defense scores by tackling a runner in his own end zone, is worth two.
Who has the ball?
Only one team can have the ball. It changes hands after a score, with a kickoff. It also changes when the offense punts, or when it turns the ball over by fumbling, throwing an interception, or failing to make a first down on fourth down.
Fair play
The officials enforce the rules. When a player breaks one, an official throws a yellow flag and the team is penalized, usually by losing yards. The game begins with a coin toss to decide who chooses first.
All the penalties
Pick a penalty to see exactly what it is and how the officials enforce it. Some fouls can be committed by more than one unit, so they appear in more than one list.
Offensive penalties
The offense does not snap the ball before the play clock runs out.
A blocker grabs, hooks or pulls a defender to stop him, instead of blocking with open hands in front of the body.
The offense lines up in a way the rules do not allow. At least seven players must be on the line of scrimmage, and the players at both ends of that line must be eligible receivers.
Only one offensive player may move before the snap, and he must not be running toward the line of scrimmage when the ball is snapped. A second player moving, or a motion player running forward at the snap, is illegal motion.
Several offensive players change positions before the snap and do not all come to a stop, set, for a full second before the ball is snapped.
On a forward pass, an offensive lineman or another player who may not catch passes runs more than one yard past the line of scrimmage before the ball is thrown.
On a forward pass, a receiver pushes off or blocks a defender so that the defender cannot play the ball.
The quarterback throws the ball away, with no eligible receiver in a position to catch it, to avoid being sacked.
A forward pass is thrown from beyond the line of scrimmage, or a team throws a second forward pass on the same play.
Two offensive players block the same defender at the same time, one high and one low, or one blocker hits a defender at the legs while another is engaged with him. It is a dangerous block that can injure the knees.
A player blocks an opponent from behind at or below the knees, when the opponent is not the ball carrier.
A player pushes an opponent from behind, above the knees, when the opponent is not the ball carrier.
A player grabs or twists the face mask of an opponent’s helmet.
A catch-all personal foul for hits beyond what the rules allow, such as hitting a player after the whistle, hitting a defenseless player, or hitting a player who is out of bounds.
A player behaves in a way that is not allowed, such as abusive language to an official or an opponent, or fighting.
A player uses words or gestures that insult or provoke an opponent, such as standing over a player he has just tackled or blocked.
A player lowers his head and makes contact with an opponent using the crown or top of his helmet.
A player moves toward his own end line and blocks an opponent who cannot see him coming, using a forearm, shoulder or helmet to hit him.
A team has more than 11 players on the field at the snap.
Defensive penalties
The offense does not snap the ball before the play clock runs out.
A player blocks an opponent from behind at or below the knees, when the opponent is not the ball carrier.
A player pushes an opponent from behind, above the knees, when the opponent is not the ball carrier.
A player grabs or twists the face mask of an opponent’s helmet.
A catch-all personal foul for hits beyond what the rules allow, such as hitting a player after the whistle, hitting a defenseless player, or hitting a player who is out of bounds.
A player behaves in a way that is not allowed, such as abusive language to an official or an opponent, or fighting.
A player uses words or gestures that insult or provoke an opponent, such as standing over a player he has just tackled or blocked.
A tackler grabs the inside back or side of the collar of the runner’s shoulder pads or jersey and pulls him down.
A tackler wraps up the runner, then swivels his hips and drops his weight onto the runner’s legs.
A player lowers his head and makes contact with an opponent using the crown or top of his helmet.
A player moves toward his own end line and blocks an opponent who cannot see him coming, using a forearm, shoulder or helmet to hit him.
A team has more than 11 players on the field at the snap.
A defensive player is past the line of scrimmage when the ball is snapped.
A defender crosses the line of scrimmage and makes contact with an offensive player or the ball before the snap.
A defender moves into the neutral zone before the snap and causes an offensive player to react, such as flinching or jumping.
A defender grabs or restricts an offensive player who is not the ball carrier, such as a receiver, in a way that stops him from getting into his route.
A defender hits or holds an eligible receiver more than five yards past the line of scrimmage, before the pass is thrown.
A defender interferes with a receiver’s chance to catch a forward pass, by hitting, grabbing or blocking him before the ball arrives.
A defender hits the quarterback after he has thrown the ball, hits him high or low, or drives his full body weight onto him as he brings him down.
Special teams penalties
A blocker grabs, hooks or pulls a defender to stop him, instead of blocking with open hands in front of the body.
The offense lines up in a way the rules do not allow. At least seven players must be on the line of scrimmage, and the players at both ends of that line must be eligible receivers.
Two offensive players block the same defender at the same time, one high and one low, or one blocker hits a defender at the legs while another is engaged with him. It is a dangerous block that can injure the knees.
A player blocks an opponent from behind at or below the knees, when the opponent is not the ball carrier.
A player pushes an opponent from behind, above the knees, when the opponent is not the ball carrier.
A player grabs or twists the face mask of an opponent’s helmet.
A catch-all personal foul for hits beyond what the rules allow, such as hitting a player after the whistle, hitting a defenseless player, or hitting a player who is out of bounds.
A player behaves in a way that is not allowed, such as abusive language to an official or an opponent, or fighting.
A player uses words or gestures that insult or provoke an opponent, such as standing over a player he has just tackled or blocked.
A tackler grabs the inside back or side of the collar of the runner’s shoulder pads or jersey and pulls him down.
A tackler wraps up the runner, then swivels his hips and drops his weight onto the runner’s legs.
A player lowers his head and makes contact with an opponent using the crown or top of his helmet.
A player moves toward his own end line and blocks an opponent who cannot see him coming, using a forearm, shoulder or helmet to hit him.
A team has more than 11 players on the field at the snap.
A defensive player is past the line of scrimmage when the ball is snapped.
A defender hits or runs into the kicker or punter in a way that is more than incidental contact, after he has kicked the ball.
A defender runs into the kicker or punter, but the contact is not violent and does not take him off his feet.
A defender makes illegal contact with the long snapper while he is in a vulnerable position right after snapping the ball on a kick.
A player on the kicking team interferes with the returner’s chance to catch a punt or kickoff, such as hitting him before the ball arrives.
A returner makes a motion that looks like a fair catch signal but is not a proper one, which could make the kicking team stop its coverage.
A player on the kick-blocking team uses a teammate for support in order to jump higher, or leaps to block a field goal or an extra point.