The following is a list of common and historically significant formations in American football. In football, the formation describes how the players in a team are positioned on the field. Many variations are possible on both sides of the ball, depending on the strategy being employed. On offense, the formation must include at least seven players on the line of scrimmage, including a center to start the play by snapping the ball. There are no restrictions on the arrangement of defensive players, and, as such, the number of defensive players on the line of scrimmage varies by formation.
