Drywall Calculator
Enter your wall size to get the drywall sheets you need, plus an estimated cost. Waste is included.
Drywall needed
Estimated cost
How to calculate drywall sheets
Drywall is sold by the sheet, and the standard sheet is 4 ft by 8 ft, which is 32 sq ft. Find the wall area, add waste for cuts, then divide by 32 and round up.
Formula: sheets = wall area (sq ft) × (1 + waste %) ÷ 32, rounded up
Worked example: 12 ft × 8 ft wall
Wall area = 12 × 8 = 96 sq ft. Add 10% waste: 105.6 sq ft. Divide by 32: 3.3, rounded up to 4 sheets.
Whole rooms
For a whole room, add up every wall plus the ceiling. You can run the total through this calculator once, or do each wall separately and add the sheets.
Which thickness?
Half-inch drywall is standard for walls. Five-eighths inch is used for ceilings and fire-rated walls. Quarter-inch is for curved surfaces and overlays.
Common wall sizes
Cost tips
Prices on this page are editable estimates, not quotes. Get 2 to 3 local quotes before you buy, and ask if delivery is included. Delivery, tax and waste can change the total a lot. Order a little extra for cuts and breakage, and confirm final quantities with your supplier or a qualified professional.
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Frequently asked questions
How many drywall sheets do I need for a 12x8 wall?
A 12 ft by 8 ft wall needs 4 sheets of 4x8 drywall, with 10% waste.
How big is a sheet of drywall?
The standard sheet is 4 ft by 8 ft, which is 32 sq ft. Longer 10 ft and 12 ft sheets exist for tall walls.
How do I count drywall for a whole room?
Add up all wall areas plus the ceiling, then run them through this calculator as one total area, or do each wall separately.
How much waste should I add?
Add 10% for straight walls and 15% for rooms with many corners, windows and doors.
What screws do I need?
Use drywall screws, about 32 per sheet, spaced 12 inches on ceilings and 16 inches on walls. This calculator counts sheets only.
Are the prices accurate?
Prices are editable estimates. The defaults are typical US figures, and your local price can be higher or lower.