An NFL Football Is Legal Anywhere Between 12.5 And 13.5 Pounds

A football is the one piece of equipment every play depends on, and the rule describing it is shorter than most people expect - and looser.

What Rule 2 specifies

The rulebook says the ball shall be made up of an inflated bladder of 12.5 to 13.5 pounds, enclosed in a pebble grained leather case in natural tan colour, without corrugations of any kind. It shall have the form of a prolate spheroid, with a long axis of 11 to 11.25 inches, a long circumference of 28 to 28.5 inches, a short circumference of 21 to 21.25 inches, and a weight of 14 to 15 ounces.

Every dimension in Rule 2 is a range, not a number.

That is a full pound of legal room on inflation alone, and an ounce on weight. Two balls can sit at opposite ends of the range and both be entirely legal.

Who decides

The rule then answers the question that matters more than the numbers: "The Referee shall be the sole judge as to whether all balls offered for play comply with these specifications." Not the league office, not the clubs, and not a machine - the Referee.

The handling chain

The same rule sets out the logistics. A League-approved inflation measurement device is provided to the officials for every game. A pump is furnished by the home club. And the balls remain under the supervision of the Referee until they are delivered to members of the ball crew just prior to the start of the game.

• 01Inflation: 12.5 to 13.5 pounds
• 02Weight: 14 to 15 ounces
• 03Long axis: 11 to 11.25 inches
• 04Long circumference: 28 to 28.5 inches
• 05Short circumference: 21 to 21.25 inches