Last updated: by Thanassis Koukoutselos
A regulation men’s basketball, used in the NBA, NCAA men’s games and boys’ high school, is a size 7: 29.5 inches (74.9 cm) around, about 9.4 inches (23.9 cm) in diameter and 22 ounces (624 g). The women’s game (WNBA, NCAA women, girls’ high school) uses a size 6: 28.5 inches (72.4 cm) around, about 9.1 inches (23 cm) across and 20 ounces (567 g).
Kids use smaller balls, sizes 3 to 5, so they can dribble and shoot with good form. Use the finder below, or the charts after it.
Basketball size finder
Basketball size chart: circumference, diameter and weight
| Size | Circumference | Diameter | Weight | Typical use |
|---|---|---|---|---|
| 7 | 29.5″ (74.9 cm) | 9.4″ (23.9 cm) | 22 oz (624 g) | Men and boys 15+: NBA, NCAA men, boys’ high school |
| 6 | 28.5″ (72.4 cm) | 9.1″ (23.0 cm) | 20 oz (567 g) | Women and girls 12+, boys 12 to 14: WNBA, NCAA women |
| 5 | 27.5″ (69.9 cm) | 8.8″ (22.2 cm) | 17 oz (482 g) | Ages 8 to 11 |
| 4 | 25.5″ (64.8 cm) | 8.1″ (20.6 cm) | 14 oz (397 g) | Ages 5 to 8 |
| 3 | 22″ (55.9 cm) | 7.0″ (17.8 cm) | 10 to 11 oz (283 to 312 g) | Ages 4 to 6, mini ball |
Circumference and weight follow manufacturer size charts (Baden and Nike). Diameter is calculated from the circumference (circumference ÷ π), and metric values are converted from inches and ounces. Brands vary slightly: Nike, for example, lists a size 7 as 29.5 to 30 inches and 20 to 22 ounces.
Basketball size by age
| Age | Boys | Girls |
|---|---|---|
| 4 and under | Size 3 | Size 3 |
| 5 to 7 | Size 4 | Size 4 |
| 8 to 11 | Size 5 | Size 5 |
| 12 to 14 | Size 6 | Size 6 |
| 15 and older | Size 7 | Size 6 |
This follows Baden’s parent guide. Nike moves players up sooner: it lists size 6 for girls from age 9 and boys aged 9 to 12, and size 7 for boys from 12. If a child plays in a league, the league’s rule wins, so ask the coach before buying.
Official ball size by league
| League or level | Ball size | Circumference |
|---|---|---|
| NBA | Size 7 | 29.5″ |
| WNBA | Size 6 | 28.5″ |
| NCAA men | Size 7 | 29.5″ |
| NCAA women | Size 6 | 28.5″ |
| High school boys | Size 7 | 29.5″ |
| High school girls | Size 6 | 28.5″ |
| FIBA men / women | Size 7 / size 6 | 29.5″ / 28.5″ |
Is 28.5 NBA size? No. A 28.5-inch ball is a size 6, the women’s and youth size. The NBA uses a 29.5-inch size 7 ball, made by Wilson since the 2021-22 season. More on that in the official NBA basketball.
Men’s vs women’s basketball size
A men’s basketball is a size 7: 29.5 inches around (74.9 cm). A women’s basketball is a size 6: 28.5 inches around (72.4 cm), one inch smaller and noticeably lighter. Every major league follows this split: the NBA and NCAA men play with a size 7, the WNBA and NCAA women with a size 6.
| Men’s (size 7) | Women’s (size 6) | |
|---|---|---|
| Circumference | 29.5 in (74.9 cm) | 28.5 in (72.4 cm) |
| Diameter | about 9.4 in (23.9 cm) | about 9.1 in (23.0 cm) |
| FIBA weight range (2024 rules) | 580 to 620 g | 510 to 550 g |
| Used by | NBA, NCAA men, FIBA men, boys 15+ | WNBA, NCAA women, FIBA women, girls 12+ |
Boys aged about 12 to 14 also usually play with a size 6 before moving up to size 7. Full weights for every size are in how much a basketball weighs.
What is the diameter of a basketball?
A size 7 basketball is about 9.4 inches (23.9 cm) in diameter, a size 6 about 9.1 inches (23 cm), and a size 5 about 8.8 inches (22.2 cm). Manufacturers quote circumference rather than diameter, because it is easier to measure on a round, inflated ball: wrap a soft tape measure around the widest part of the ball, over the channels, and divide by 3.14 to get the diameter.
What does size 7 mean?
The size number is just a label for a standard circumference. Size 7 means a 29.5-inch ball, the full-size men’s ball, so yes, size 7 is “full size”. Size 6 is full size for women’s basketball.
Good balls in each size
Popular models that come in the sizes above. These are links to Amazon; check the size option before you buy.
- Indoor, sizes 5, 6 and 7: Wilson Evolution, the classic indoor composite leather ball used by many high school teams.
- Indoor and outdoor, sizes 5, 6 and 7: Spalding React TF-250, a composite ball that also handles outdoor courts.
- Outdoor, mini to size 7: Wilson NBA DRV Series, a rubber outdoor ball in every size from mini to official.
- Size 4: Mikasa BX1000, a rubber ball that comes in size 4, which few brands make.
- Size 3 mini: Wilson WNBA Authentic Outdoor Mini, a 22-inch ball for the youngest players.
Want to know what each ball weighs in detail? See how much a basketball weighs. Setting up a hoop at home? See the best in-ground basketball hoops.
Related guides: FIBA basketballs, how much air a basketball needs, types of basketballs.
FAQ
What size basketball for a 7-year-old?
A size 4 (25.5 inches). A small 5- or 6-year-old can start with a size 3 mini ball.
What size basketball for an 8-year-old?
Eight is the crossover age: the chart puts size 4 at ages 5 to 8 and size 5 at ages 8 to 11. Use the size your league plays with. If there is no league rule, a size 5 (27.5 inches) will last longer as the child grows.
What size basketball for a 10-year-old?
A size 5 (27.5 inches), the standard youth ball for ages 8 to 11.
What size basketball for a 12-year-old?
A size 6 (28.5 inches) for boys and girls. Boys usually move to a size 7 at 15, girls stay on size 6.
What size is a regular basketball?
A “regular” or full-size basketball is a size 7, 29.5 inches around, the size used in the NBA, men’s college and men’s FIBA basketball. The regular women’s ball is a size 6, 28.5 inches.
What is a regulation size basketball?
For men it is a size 7 (29.5 inches, about 22 ounces); for women it is a size 6 (28.5 inches, about 20 ounces).
Sources
- How to Pass a Basketball (5 effective tips) - August 25, 2022
- Learn How to Spin a Basketball on your Finger in less than 3 minutes - July 18, 2022
- Where Are Basketballs Made? Spalding, Wilson and Molten (2026) - June 10, 2022