Drywall Calculator
Drywall or plasterboard sheets for a room, with screws, tape and joint compound.
About this tool
Enter the room's length, width and wall height, the area of doors and windows, and a waste percentage. Choose the sheet size and whether to include the ceiling. The calculator shows the number of sheets, the area to board, and rough quantities of screws, joint tape and ready-mixed joint compound.
How much drywall to buy
Wall area is the room's perimeter ร height. Add the ceiling, subtract doors and windows, add about 10% for offcuts and divide by the sheet area. A 4 ร 3.5 m room with 2.4 m walls has 36 mยฒ of wall. Add the 14 mยฒ ceiling and take off 3 mยฒ of openings to get 47 mยฒ. With waste, that is 18 sheets of 1200 ร 2400 mm plasterboard. In feet, a 13 ร 12 ft room with 8 ft walls also needs 18 sheets of 4 ร 8 ft drywall. Larger sheets laid horizontally mean fewer joints to tape and fill. The finishing estimates are rules of thumb: about one screw, 0.37 ft of tape and just under a hundredth of a US gallon of ready-mixed compound per square foot of board, enough for three coats. Honest limits: ceilings, bathrooms and fire-separating walls may need thicker, moisture-resistant or fire-rated board, and screw spacing rules vary, so follow the manufacturer's guidance. The paint calculator plans the finish, the area calculator measures odd walls and the unit converter switches units.
Frequently asked questions
How many sheets of drywall do I need for a room?
Divide the wall and ceiling area, minus openings and plus about 10% waste, by the sheet area. A 13 ร 12 ft room with 8 ft walls and a ceiling needs about 18 sheets of 4 ร 8 ft.
How many screws per sheet of drywall?
Roughly 32 for a 4 ร 8 ft sheet on walls, or about one per square foot. Ceilings usually need closer spacing.
What is the difference between drywall and plasterboard?
They are the same product. Drywall is the North American name and plasterboard the British one.
Is my data saved?
No. The calculation runs in your browser and nothing is stored or sent.