The standard weight of a basketball used in professional leagues is 22 ounces, or 620 grams. This weight is consistent across major leagues, including the NBA, ensuring uniformity during competitions. The official size for men's basketball is also standardized to a circumference of about 29.5 inches, while women's professional basketballs typically weigh around 18 ounces. This uniformity in weight and size is crucial for both player performance and fair play during games.