Original: Basketball size The regulation WNBA ball is a minimum 28.5 inches (72.4 cm) in circumference, which is 1.00 inch (2.54 cm) smaller than the NBA ball.
Simplified: Basketball size The correct size for the ball in WNBA (Women's National Basketball Association) rules is a minimum of 28.5 inches (72.4 cm) in circumference. This is 1.00 inch (2.54 cm) smaller than the NBA ball.