Size is a specification.
| Size | Circumference | Weight |
|---|---|---|
| 7 | 750–770 mm | 580–620 g |
| 6 | 715–730 mm | 510–550 g |
| 5 | 685–700 mm | 465–495 g |
| Lightweight 5 | 685–700 mm | 360–390 g |
FIBA specifies size 7 for men, size 6 for women, and size 5 or lightweight 5 for mini basketball.
Use the marking on the ball.
FIBA requires a recommended inflation marking and a rebound test: a drop from about 1,800 mm should rebound 1,035–1,085 mm, measured underneath the ball. NBA Rule 1 specifies 7½–8½ pounds pressure.
Circumference is not diameter.
Circumference goes around the ball. Diameter runs straight through its centre. When comparing products, match the same measurement and the same size standard. “Official size” without a named size or competition gives you too little information.