Distributions from AAA From TaxAlmanac, A Free Online Resource for Tax Professionals Note: You are using this website at your own risk, subject to our Disclaimer and Website Use and Contribution Terms.
As of 2008 the circumference of a regulation size baseball is between nine and nine and a quarter inches which converts to between about 7.3 cm and 7.5 cm in diameter according to the official rules of Major League Baseball (MLB).
In 1860 the dimensions agreed upon during the yearly convention were changed and the new playing rules stated that the weight of the ball should be between five and three-fourths ounces and between nine and three-fourths to ten inches in circumference.. 7.9 - 8.1 cm. Heitz, Thomas R. Baseball.