What Size Is an NBA Basketball? Official Dimensions Explained

By Emma Wilson · September 30, 2028

An NBA basketball is size 7, with a circumference of 29.5 inches (74.9 cm) and a standard diameter of approximately 9.4 inches (23.8 cm). This size is used by male players aged 12 and up, including professionals in the NBA.

Understanding NBA Basketball Size

The official size of an NBA basketball is standardized to ensure consistency across games and player performance. Known as Size 7, this ball is designed for adult male players competing at high levels, particularly in professional leagues like the NBA.

Key Specifications of an NBA Basketball

Circumference: 29.5 inches (74.9 cm)
Diameter: Approximately 9.4 inches (23.8 cm)
Weight: 22 ounces (624 grams)
Size designation: Size 7
Inflation pressure: 7.5 to 8.5 psi

Why Size Matters in Professional Basketball

The exact dimensions of an NBA basketball are crucial for gameplay, affecting dribbling, shooting, and passing. A consistent size ensures fairness and allows players to develop muscle memory and skill precision.

Impact on Player Performance

Uniform ball size enables predictable handling and control.
Larger hands benefit from the 29.5-inch circumference, allowing better grip and spin control.
Bounce consistency is maintained due to regulated air pressure and material composition.

Comparison Across Different Basketball Sizes

While the NBA uses Size 7, other leagues and age groups use different sizes tailored to physical development and skill level.

Size	Circumference (inches)	Circumference (cm)	Diameter (inches)	Weight (oz)	Weight (g)	Intended Users
7	29.5	74.9	9.4	22	624	NBA, Men 12+
6	28.5	72.4	9.1	20	567	WNBA, Women 12+, Boys 9–11
5	27.5	69.8	8.8	17	482	Children 9–11
4	25.5	64.8	8.1	14	397	Youth under 9
3	22	55.9	7.0	10	283	Toddler play

Table data source:1, 2

The data shows a clear progression in ball size relative to age and gender. The NBA's Size 7 ball is the largest standard basketball, optimized for adult male athletes. The WNBA uses a slightly smaller Size 6 ball, which accommodates average hand size differences while maintaining competitive integrity.

Frequently Asked Questions About NBA Basketball Size

What size is an official NBA basketball?

An official NBA basketball is Size 7, with a circumference of 29.5 inches (74.9 cm) and a weight of 22 ounces (624 grams).

Is an NBA basketball always 29.5 inches around?

Yes, all NBA game balls have a standardized circumference of 29.5 inches. This measurement is strictly enforced to maintain uniformity across all games and venues.

Can women use an NBA-sized basketball?

While women can physically use a Size 7 ball, the WNBA officially uses Size 6 (28.5 inches) for better handling and performance alignment with average hand size and strength.

What is the diameter of an NBA basketball?

The approximate diameter of an NBA basketball is 9.4 inches (23.8 cm), derived from its 29.5-inch circumference.

Do NBA basketballs vary in size between brands?

No, regardless of brand (e.g., Spalding, Wilson, or Nike), all NBA-approved balls must meet the exact size and weight specifications: 29.5 inches in circumference and 22 ounces in weight.