How the drywall calculator works
Area divided by sheet size, plus waste. The calculator takes your total drywall area (walls plus ceiling if included) and divides by the sheet size — 32 sq ft for a 4 x 8 ft sheet, 40 for 4 x 10, 48 for 4 x 12 — then adds your waste allowance (10% is typical) for cuts around doors, windows and outlets.
Fasteners and finishing are estimated at 32 screws per sheet, one gallon of joint compound per 100 sq ft, and one 250 ft roll of joint tape per 400 sq ft. 4 x 12 ft sheets mean fewer seams on long walls, but they are heavy — hang them with two people.
Painting after the drywall? Use the paint calculator.