Drywall Calculator
Enter the room's dimensions and sheet size to calculate how many drywall sheets to buy, plus the screws, joint tape and compound that go with them.
Unit
Room dimensions (feet)
Door and window openings are deliberately not deducted: the cut-outs come from sheets you still buy, and the offcuts are rarely big enough to reuse. Screws assume roughly 12 in spacing on studs, tape runs about 0.4 linear ft per ft² of board, and all-purpose compound covers roughly 110 ft² per gallon across three coats.
Frequently asked questions
How many drywall sheets do I need for a room?
Multiply the room perimeter by the ceiling height for wall area, add the ceiling if you are boarding it, add a waste buffer, then divide by the coverage of one sheet — 32 ft² for a standard 4 × 8. A 16 × 12 ft room with 8 ft ceilings comes to 640 ft² including the ceiling — 20 sheets flat, 22 once a 10% waste buffer is added.
Should I deduct doors and windows?
Not for the order. The cut-outs come from sheets you still have to buy, and the offcuts are seldom large enough to use elsewhere. Deducting openings is how installers end up one sheet short on the last wall.
What size drywall sheets should I buy?
4 × 8 ft sheets are the default because two people can carry and lift them. Longer 4 × 12 sheets produce fewer butt joints, which means less taping and a flatter finished wall, but they are heavy and awkward in a stairwell or a small room.
How much joint compound and tape will I need?
Allow roughly one gallon of all-purpose compound per 110 ft² of board across three coats, and about 0.4 linear feet of tape per square foot of board. Buy more compound than you think — sanding back a thin coat is much harder than applying another.
How many screws per drywall sheet?
About 32 for a standard 4 × 8 sheet, assuming screws every 12 inches along each stud. Ceilings take more, usually every 8 inches, because gravity works against the board rather than with it.
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