Standard sizes for drywall include 4 feet by 8 feet, 4 feet by 9 feet, 4 feet by 10 feet, 4 feet by 12 feet, and 4 feet by 14 feet. The most common size is the 4 feet by 8 feet size. Specialized drywall stores may have additional sizes.
Drywall sizes vary depending on the thickness of the board. For the thinnest offerings, which are 1/4-inch and 3/8-inch thick, the only size that is typically available is the 4 feet by 8 feet size. For the thicker offerings, which are 1/2-inch and 5/8-inch thick, all five sizes are fairly common.