Basketball sizes vary depending on the league or governing body for a particular basketball game. Basketballs are measured by circumference, inflation pressure or weight. According to USA basketball, balls should be made of leather or synthetic leather. A properly inflated ball of the correct size for level of play is important to ensure safety and skill development.
The NBA and WNBA
- NBA: 29.5 inches in circumference; inflated between 7.5-8.5 pounds per square inch
- WNBA: Maximum circumference of 29 inches; inflated between 7.5-8.5 pounds per square inch
The NCAA
- NCAA Men's Basketballs: Maximum circumference of 30 inches; seams must be no wider than 1/4 inch; weight of approximately 22 ounces
- NCAA Women's Basketballs: Maximum circumference of 29 inches; maximum weight of 20 ounces; seams no wider than 1/4 inch
FIBA
- Men's international: Circumference of 78 centimeters (30.7 inches); referred to as a size 7
- Women's international: Circumference of 74 centimeters (29 inches); referred to as size 6
When dropped on the playing floor from a height of 1,800 millimeters (6 feet) the ball should bounce to a height between 1,200 millimeters and 1,400 millimeters (47 to 55 inches), measured to the top of the ball.
Youth Sizes
Most youth or junior basketball leagues for players 8 years old and above will use a collegiate or NBA size basketball. For players younger than 8, smaller sizes can be used. Most youth leagues will use basketballs between 28 and 29 inches in circumference.