The standard weight of a volleyball in both professional beach and indoor competition is between 8.36 and 9 ounces. This is based on the rule book of the Federation of International Volleyball (FIVB), the governing body of Olympic and international play.
Each regulation ball must have a circumference between 25.59 and 26.38 inches and needs to also possess an inside pressure of 4.27 to 4.62 pounds per square inch. Balls must also be spherical in shape, with a flexible leather or synthetic leather case and a rubber or similar material bladder inside. Balls may be a uniform light color or combination of colors.