Overview
Generally speaking, both the league and the players determine the size of the basketball used, but it is important to take into consideration that playing with the correct basketball size enhances the safety and playability of the game. League regulations typically include the ball's circumference, weight, inflation pressure, and sometimes the material type or manufacturer.
NBA
The official ball used in the National Basketball Association (NBA) is made by Spalding, and each one has to be officially approved by the NBA. The official ball is 29.5 inches in circumference, inflated to be between 7.5 and 8.5 psi, and weighs 22 oz. These dimensions are typically referred to as a "Size 7" ball. NBA basketballs are constructed of orange leather with black lettering.
WNBA
Similar to the official ball used by the NBA, the Women's National Basketball Association (WNBA) only uses basketballs constructed by Spalding. However, this ball is slightly smaller, and is considered to be a "Size 6" ball. The official ball must be between 28.5 and 29 inches in circumference, inflated to no more than 9 psi, and weigh between 18 and 20 oz. The WNBA basketball is constructed of alternating patterns of orange and white leather.
FIBA
Basketballs used in International Basketball Federation (FIBA) play must be a size 7 for men's or size 6 for women's competition. FIBA requires manufacturers to be certified by FIBA, and they must be willing to submit their ball to FIBA for testing and certification procedures. The official FIBA basketballs must be between 749mm (29.48 inches) and 780mm (30.7 inches) in circumference, weigh between 567 and 650g, and must bounce to a height of at least 1300mm (51.2 inches) after being dropped from a 1800mm (70.8 inches) height. FIBA basketballs must be made of leather and bear the FIBA logo.
Men's NCAA
The official ball used in the National Collegiate Athletic Association (NCAA) is subject to less rigorous requirements than those used in the NBA or FIBA leagues. There is no official manufacturer for basketballs used in NCAA competition. Simply put, for men's competition the official ball should be a size 7. Specifically, the ball should measure between 29.5 and 30 inches in circumference, should weigh between 20 and 22 oz., and should bounce to a height of 49 to 54 inches when dropped from 6 feet.
Women's NCAA
For women's play, the NCAA requires a size 6 basketball, with a circumference between 28.5 and 29 inches, weight of 18 to 20 oz., and bounce of between 51 and 56 inches when dropped from 6 feet. The NCAA does not set specifications for color or material used. For indoor games such as regular NCAA play, the ball is typically constructed of leather, and is orange in color with black ribbing and lettering.
