| | NFL | College football |
| Feet in-bounds required for a completed pass | Two | One |
| Down-by-contact rule | Yes, a player is active until he is tackled or forced down by a member of the opposing team | No, a player is automatically ruled down when any part of his body other than the feet or hands touches the ground |
| Penalty for defensive pass interference | Automatic first down at the spot of the foul | Automatic first down, with the lesser of 15 yards from the previous spot or the spot of the foul |
| Clock temporarily stops after a first down | No | Yes, during the final two minutes of each half |
| Line of scrimmage following a missed field goal | The greater of the spot of the kick or the opposing team's 20-yard line | The greater of the previous line of scrimmage or opposing team's 20-yard line |
| Starting point of a one- or two-point conversion | 2-yard line on 2-point conversions; 15-yard line on 1-point conversions | 3-yard line |
| Overtime | Modified sudden death: both teams get the opportunity to possess the ball in overtime; if kicking team scores a safety on first possession, the game is over; otherwise, whoever is ahead after one possession wins it. Should the tie persist following a possession by each team, whoever scores next wins it. In the regular season, only one 10-minute overtime is played and games may end in a tie. Postseason games play multiple 15-minute periods until there is a winner. | Each team is given one possession from its opponent's twenty-five-yard line with no game clock (first 2 possessions; thereafter, from the opponent's 3-yard line). The team leading after both possessions is declared the winner. If the teams remain tied, this procedure is repeated once more; if a touchdown is scored, they must attempt a two-point conversion. After double overtime, and if the score is still tied, all subsequent overtime possessions consist solely of two-point conversions. Games may not end in a tie. |
| Instant replay | Coaches are issued two challenges to request a review for all other plays. A third challenge is awarded if at least one is successful. Plays during the final two minutes of each half and all overtime periods are subject only to booth review. All turnovers and plays ruled on the field to have scored points are automatically reviewed regardless of game time. Coaches are not allowed to challenge in either situation and may risk an unsportsmanlike conduct penalty if they attempt to do so; coaches cannot be disqualified on second unsportsmanlike. | Each coach receives only one challenge. If that challenge is successful, a second challenge is allowed. All plays are subject to booth reviews. |
| Placement of ball following a touchback | Following kickoffs or free kicks after a safety: a kickoff that lands in the landing zone and bounces into the endzone is live and must be returned or downed. If downed, the ball is placed on the receiving team's 20-yard line. If a kickoff goes out of the back of the endzone, the ball is placed on the receiving team's 30-yard line.All other touchback situations: 20-yard line of the team receiving possession | Receiving team's 25-yard line, except that a fair catch on a kickoff or free-kick after a safety between the receiving team's 25-yard line and the goal line is treated as a touchback, with the ball placed on the 25 |
