Regulations

The current regulations mandated by the R&A and the USGA state that diameter of the golf ball cannot be any smaller than 1.680 inches. The maximum velocity of the ball may not exceed 250 feet per second under test conditions and the weight of the ball may not exceed 1.620 ounces.

Until 1990 it was permissible to use balls of no less than 1.62 inches in diameter in tournaments under the jurisdiction of the R&A^[3].