Two-point conversion

In gridiron football, a two-point conversion, two-point convert, or two-point attempt is a play a team attempts instead of kicking a one-point conversion immediately after it scores a touchdown. In a two-point conversion attempt, the team that just scored must run a play from scrimmage close to the opponent's goal line and advance the ball across the goal line in the same manner as if they were scoring a touchdown. If the team succeeds, it earns two additional points in addition to the six points for the touchdown, for a total of eight points. If the team fails, no additional points are scored.

Conversion attempts are untimed plays in American football, and in the Canadian game they are untimed in the final three minutes of each half. If any time remains in the half, the team that scored the touchdown will proceed to a kickoff after their conversion attempt.

To attempt the two-point conversion, the team that just scored must run a scrimmage from the 5-yard line in amateur Canadian football, 3-yard line in professional Canadian football, 3-yard line in amateur American football, or 2-yard line in professional American football. In professional American football, there is a small dash to denote the line of scrimmage for a two-point conversion; it was also, until 2014, the line of scrimmage for a point-after kick ("extra point").

Various sources estimate the success rate of a two-point conversion to be between 40% and 55%, significantly lower than that of the one-point conversion (which has a 90% to 95% success rate in the NFL),^[1] although, because of the higher value, a higher expected value is achieved through the two-point conversion than the extra point.^[2][3]

In American college, professional, and Canadian football (as well as, for a significant period of time, the Arena Football League, where missed extra points were rebounded back into the field of play), a conversion attempt where the defense gains possession of the ball can be returned by the defense to the other end zone to give the defensive team two points. The team that scored the touchdown then kicks off as normal.

This is rare because of the infrequent use of the two-point conversion and the rarity of blocked conversion kicks, combined with the difficulty of returning the ball the full length of the field. It has proven the winning margin in some games, the first such college game occurring September 10, 1988, when St. John's defeated Iona College, 26–24.^[13] Only once has a player scored two defensive two-point conversions in a game: Tony Holmes of the Texas Longhorns in a 1998 game against the Iowa State Cyclones on October 3.

The NFL originally had no provision for defensive two-point conversions, and its rules used to state that a conversion was automatically blown dead and ruled as "no good" as soon as the defense gained possession of the ball. On May 19, 2015, the NFL owners adopted a proposal to permit a defensive two-point conversion for the 2015 season. On May 20, 2016, the owners adopted a further proposal called the two-point fair-play rule: this prevents the defense from getting a turnover during a two-point conversion and then intentionally committing a foul to increase their chance at a two-point return. If the defense gains a turnover and then commits a foul, the offense will have the option to accept the penalty and attempt the try again. It has not yet been enforced in the NFL, but a similar rule has been enforced on two occasions in the CFL.^[14][15]

Stephone Anthony of the New Orleans Saints became the first NFL player to score a defensive two-point conversion, returning a blocked extra-point kick from Graham Gano of the Carolina Panthers on December 6, 2015.^[16] On December 4, 2016, Eric Berry of the Kansas City Chiefs became the first NFL player to return an interception for a defensive two-point conversion, which was thrown by quarterback Matt Ryan of the Atlanta Falcons.^[17]

The NCAA has allowed defensive two-point conversions in college football since the 1988 season. In that first season, there were 20 defensive conversions scored among all NCAA divisions, with two in Division I-A.^[18][19][20] The first defensive conversion in NCAA Division I-A was scored by Bill Stone of Rice University in a 54–11 loss to Notre Dame on November 5, 1988.^[21][a] The first college player to score a defensive two-point conversion was Rod Beauchamp of Colorado School of Mines on September 3, 1988, in a 36–2 loss to Hastings College, after the Hastings center snapped the ball over the holder's head; even though the rule states the ball cannot be advanced when it hits the ground in this manner, the score stands once the referee declares the game over.^[24]

The first defensive conversion following a blocked extra-point kick was scored by Springfield College in a 40–33 win over WPI on September 9, 1988.^[25]

High schools that follow the rules of the National Federation of State High School Associations (all U.S. high schools except those in Texas, which uses NCAA rules instead) do not allow defensive runbacks of recovered conversion attempts, and any recovery of the ball by the defense during the try is immediately blown dead and ruled as "no good."

Rules in high school, college and professional football dictate that when a safety occurs during a two-point conversion or point-after kick (officially known in the rulebooks as a try), it is worth one point. It can be scored by the offense in college and professional football (following an NFL rule change in 2015) if the defense obtains possession of a live ball in the field of play, propels the ball into its own end zone, and the ball is then downed there with the defense in possession. This event has only occurred four times in NCAA Division I history. Before 2015, the only scenario in which the offense could have scored a one-point safety in the NFL would have involved, on a conversion attempt in which the ball was not kicked by the offense, the defense kicking or batting a loose ball out the back of the end zone without taking possession of it.^{[26][27][28][29]}

A conversion safety can be earned by the defense if the offense retreats with the ball all the way back into its own end zone. Two potential scenarios include (1) an errant snap or a fumble that is bobbled repeatedly until the offensive team recovers the ball in, or bats the ball through, its own end zone (similar situations have been documented in regular play from scrimmage^[30] and are more likely in arena football with its much shorter, narrower and bounded field of play), and (2) a defender attempting a defensive two-point conversion and fumbling the ball, with the offensive team recovering and establishing possession outside the end zone, then downing the ball in its own end zone. Although such a conversion safety has never been scored by the defense, this rule provides the only way in American professional football that a team could finish the game with a score of one point. (Canadian football allows another one-point play called the single or rouge).^[31] Following a 2021 rule change in college football, triple overtime and thereafter involves teams attempting two-point conversions rather than running plays from the 25-yard line. The rules regarding safeties on these plays are the same as for any other conversion attempt, opening up additional ways for a team to finish the game with exactly one point (though in this scenario, a game would have to remain scoreless through double overtime to achieve this).

The high school football rulebook acknowledges the conversion safety, awarding one point for it, but also immediately ends a play if the opposing team gains possession of the ball, a rule similar to the one the NFL used before 2015. Thus, any situation that requires the defense to gain possession of the ball cannot result in a conversion safety in games where that rulebook is used.

The coaches' choice of whether to attempt a one- or two-point conversion depends on the game's current score, the amount of time remaining, and their assessment of their team's chance of success.^[32]

Analysis of historical data finds that the two-point conversion is successful about half the time, whereas one-point kicks are almost always successful. Therefore, the expected value of both options is roughly similar, with the critical factor being whether the chance of a successful two-point conversion is more or less than half that of a successful kick.^[32][33] However, the mathematics regarding maximizing a team's chances of winning are more complicated. For example, late in a game, a team that is one point up after a touchdown would gain little benefit from a one-point attempt, because regardless of success, the team would still lose if the opposition later scored a field goal. In such a situation, the two-point conversion would be the better option. If successful, an opposition field goal would then only tie the game.^[32]

A more complicated scenario is when a team is trailing by 14 points. The team could choose to go for two, because, if successful, the team could then kick an extra point following the next score to secure a win. On the other hand, if the two-point conversion fails, the team still has a chance to succeed on the next two-point conversion to get to fourteen. Mathematically, therefore, the minimum probability of converting a two-point try either on the first attempt (securing a win) or the second (securing a tie in regulation time) must be higher than the maximum probability of missing both (securing a loss). This occurs when the probability of missing both is 0.618 × 0.618, or 38.2%.^[34] As long as the probability of converting any individual two-point attempt is higher than 38.2% percent, it is optimal to adopt this strategy.^[35][36] Notably, Texas Longhorns coach Darrell Royal successfully used this strategy to defeat Arkansas in 1969's Game of the Century.

An analysis can be done for all situations, resulting in a table that can be consulted when a decision is needed.^[32] A chart made by UCLA offensive coordinator Dick Vermeil in the early 1970s is one of the most well-known.^[37][38]

In practice, two-point conversion attempts are rare, being done only after less than 1-in-10 touchdowns in the NFL.^[33] This proportion rose after the one-point kick was moved back to the 15-yard line (see Extra point adjustment above), which increased the difficulty and decreased the success rate of scoring the extra point.^[33][39]