at http://www.hud.gov/offices/reac/pdf/pass_dict2.3.pdf (325 Pages, 343 KB) Additional clarification to these definitions is contained in the REAC PASS Compilation Bulletin which can be found at http://www.hud.gov/offices/reac/pdf/pass_bulletin.pdf (24 Pages, 275 KB)
An official NFL football is slightly larger than high school or other professional leagues. The length should measure about 11 inches from tip to tip, and the in circumference at the center of the football should measure about 22 inches.imilar 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. The Digest of Rules of the NFL explains the official size requirements for the football, along with other basic rules for playing the game.
A major variant of football is arena football, played by the Arena Football League (AFL). Arena football has eight-player teams and uses an indoor field 50 yards (46 m) in length, excluding end zones, and 28.3 yards (25.9 m) wide. Punting is illegal, and kickoffs are attempted from the goal line.