A baseball is a ball used in the sport of baseball. A regulation baseball is 9 to 9⅛ inches (229 to 233 mm) in circumference, and weighs 5 to 5½ ounces (140 to 156 g). It is composed of cork covered by black rubber, with red stitching.
The ball has a seam that is 0.036 inches (0.91 mm) deep.
A baseball weighs between 5 and 5 1/4 ounces. It is 9 to 9 1/4 inches in circumference and has 108 double stitches.
How Hard Is It To Hit a Major League Fastball (According to Science)?

Credit: bestbaseballguides.com
How Much Does a Major League Baseball Weigh
A Major League Baseball weighs between 5 and 5.25 ounces, or 141 and 148 grams.
Conclusion
A Major League Baseball (MLB) weighs between 5 and 5 1/4 ounces. The weight of a baseball can vary slightly depending on the manufacturer. MLBs are typically made from cowhide and vulcanized rubber.