Official golf balls measure 1.68 inches in diameter and weigh 1.62 ounces. Golf balls must also be spherically symmetrical and meet construction and performance specifications.
The United States Golf Association sets the rules for golf ball size, shape and performance for balls used in tournament play. Those rules are found in Appendix III of the association's official Rules of Golf document. In addition to size and shape specifications, Appendix III states that golf balls must be made using traditional techniques and form. Performance standards cover initial velocity and overall distance capabilities. The USGA regularly tests conforming balls and new balls submitted by manufacturers for performance compliance.