By regulation it may be no more than 2.75 inches (7.0 cm) in diameter at the thickest part and no more than 42 inches (1.067 m) in length. Although historically bats approaching 3 pounds (1.4 kg) were swung, today bats of 33 ounces (0.94 kg) are common, topping out at 34 to 36 ounces (0.96 to 1.02 kg).