There are 11 players on the field per team in American football. Each team can have eleven players on the field during a play, making 22 active players when both offenses and defenses are counted together.
The eleven-player structure applies to the standard forms of American football played outdoors and in major professional and college competitions. On offense, the lineup commonly includes a quarterback, running backs, wide receivers, tight ends and offensive linemen. The defense usually consists of defensive linemen, linebackers and defensive backs, although formations vary considerably.
Teams may substitute freely between plays in many versions of the game, so a roster contains far more than eleven people. In the NFL, game-day active rosters include dozens of players, but only eleven from one team may participate in a particular down. A team can be penalized for having too many players in the huddle or on the field.
This number is often confused with other football codes. Canadian football uses 12 players per team, while arena football traditionally uses fewer. The number also differs from American football’s 11-player roster on each side of a play.