A football is a ball used to play one of the various sports known as football. In the distant past, crude balls such as inflated pigs' bladders were used, but balls are now designed by teams of engineers to exacting specifications. Each code of football uses a different ball, though they all belong to one of two different basic shapes:

1. a sphere: used in Association football (also called soccer in some countries) and Gaelic football
2. a prolate spheroid ('oval-shaped')
   • either with rounded ends: used in Rugby football and Australian football
   • or with more pointed ends: used in American football and Canadian football

   The precise shape and construction of footballs is typically specified as part of the rules and regulations.

   Association football

   See also: History of association football balls

   Dimensions

   Law 2 of the game specifies that the ball is an air-filled sphere with a circumference of 68–70 cm (or 27–28 inches), a weight 410–450 g (or 14–16 ounces), inflated to a pressure of 8–12 psi, and covered in leather or "other suitable material". The weight specified for a ball is the dry weight, as older balls often became significantly heavier in the course of a match played in wet weather. The standard ball is a Size 5, although smaller sizes exist: Size 3 is standard for team handball and Size 4 in futsal and other small-field variants. Other sizes are used in underage games or as novelty items.

   Construction

   

   

   

   

   The official FIFA World Cup football for Germany 2006 matches was the 14-panel Adidas +Teamgeist. It was made in Thailand by Adidas, who have provided the official match balls for the tournament since 1970, and is a "thermally bonded" machine-pressed ball, rather than a traditionally stitched one. Adidas will continue to supply the official football for the 2010 and 2014 World Cups.

   Another ball with an innovative pattern is the 26-panel Mitre PRO 100T.

   There are also indoor footballs, which are made of one or two pieces of plastic. Often these have designs printed on them to resemble a stitched leather ball.

   Child labour

   About 80% of association footballs are made in Pakistan. 75% of these (60% of all world production) are made in the city of Sialkot. Child labour was commonly used in the production of the balls. In 1996, during the European championship, activists lobbied to end the use of child labour. This eventually led to the Atlanta Agreement, which seeks to reform the industry to eliminate the use of child labour in the production of balls. This also led to a centralisation of production, which on the one hand would make it easier for the Independent Monitoring Association for Child Labour (IMAC) - an organization created to watch over the Atlanta Agreement - to make sure no child labour occurred, on the other hand often forced workers to commute further to get to work. According to the Fédération Internationale de Football Association (FIFA), the problem of eliminating the use of child labour is extremely complex, and that FIFA itself has neither "the experience nor the means to eradicate this wide-reaching problem on its own." .