What Is the Official Size of the NFL Football?

The National Football League – the NFL – is a league composed of the best football players in the world. Similar to other levels of football, the NFL uses an egg-shaped football, but the NFL has specific rules to the size, shape and materials used for the football.

There are 2 NFL rules regarding the ball:

1. Ball Dimensions

The Ball must be a hand selected Wilson with the signature of the Commissioner of the League, Roger Goodell.

The ball should be an inflated urethane bladder enclosed in a pebble grained, leather case and a natural tan color without corrugations, wrinkles or ridges.

The ball measurement is 11 to 11 1/4 inches long, a 28 to 28.5 inch long circumference and a 21 to 21.25 inch short circumference.

The football should weigh between 14 to 15 ounces.

2. Ball Supply

The Referee will be supplied 12 primary balls two hours and 15 minutes prior to the game for testing. The home team makes an additional 12 backup balls available for testing and the visitors may bring 12 backup balls for testing by the referee when the game is played in an outdoor stadium.

The Eight Special Balls for Kicking

All games have eight new footballs, specially sealed in a box, shipped by the manufacturer directly to the referee. The referee will open the special box with eight footballs 2 hours and 15 minutes prior to the game. The placekicker will kick only these eight special footballs during the game.

The NFL Center can request a playable ball

The offensive team center, the position that hikes the football, may request a playable ball with the field conditions deem the ball unplayable.

Such conditions according to the NFL rules are in case of:

1. rain
2. wet, muddy, or slippery field

Measurements

The NFL has set measurement rules for the overall length and largest circumference at the center of the football. An official NFL football is slightly larger than high school or other professional leagues.

The ball measurement is 11 to 11 1/4 inches long, a 28 to 28.5 inch long circumference and a 21 to 21.25 inch short circumference.

Weight

Overall weight and air pressure are specific in the NFL, too. The football and materials weighs about 14 to 15 oz., and is the ball is inflated to about 12.5 to 13.5 lbs. per square inch. Footballs used in the NFL are inflated to 13 psi, but a proper range can fall between 12.5 and 13.5 psi..

These weight and air pressure measurements create consistency among the many footballs required in a game.

Ideal Gas Law and the Football

Under the Ideal Gas Law, the working theory is that the air pressure in the balls would rise during warm days and fall during cold days. When the NFL measured footballs at halftime of games, they found this to be consistent. Indeed, consistent with weather conditions or for other reasons, the NFL found during the 2015 season, measured footballs were beyond the permitted 12.5 to 13.5 PSI levels, but correlated to the Ideal Gas Law.

Materials

The NFL rules also govern the dimension of materials, the number of layers and the pattern of design. Four leather panels are weighed, measured and inspected for blemishes before being sewn together. The top two panels are sewn together with white leather laces. Inside the leather panels is a 3-ply VPU rubber bladder or interior lining that holds the air.

Inspection

Before every NFL football game, the home club supplies 36 footballs for outdoor contests and 24 footballs for indoor ones. An additional 12 footballs are marked with the letter “K,” and are used specifically for kicking.

The referee inspects every football two hours before the game to ensure it meets the official size, weight and air pressure requirements. After deflategate in 2015, the NFL measures the football at halftime too.

The New England Patriots Deflategate Controversy

In January, 2015 during an AFC championship playoff game against the Indianapolis Colts, the New England Patriots were accused of using deflated footballs. Based on the text messages between then-ball boys John Jastremski and Jim McNally, the Patriots may have been doing something that stretched beyond the NFL rulebook. However, the next season, New England Patriots Quarterback Tom Brady was ultimately suspended four games.