Drywall Calculator
How much drywall do you need? Enter your room size for sheets and cost.
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Wall area—
Estimated cost—
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How this calculator works
It calculates your total wall area (room perimeter × height), adds 10% for waste and cuts, and divides by the area of one drywall sheet.
Worked example — a 12 ft × 12 ft room, 8 ft walls, 4×8 sheets:
Perimeter 48 × 8 = 384 sq ft × 1.10 = 422 ÷ 32 = 14 sheets.
Don’t forget the ceiling
This estimate covers walls. If you’re also drywalling the ceiling, add the room’s floor area (length × width) and divide by your sheet size for the extra sheets.
Frequently asked questions
What size drywall sheet should I buy?
4×8 ft sheets are easiest to handle solo; 4×12 ft sheets mean fewer seams but need two people.
How much extra drywall for waste?
About 10% covers offcuts and damaged sheets on a typical room.
Planning a wall or paint project
Surface condition matters as much as area. Rough, porous, repaired, or strongly colored surfaces may need extra primer or paint. Check the coverage printed on the product you plan to use and account for trim, ceilings, openings, and a second coat where applicable.
How to use this estimate
- Measure the project in the units shown and recheck your measurements before ordering.
- Use the waste allowance as a planning buffer, not as a substitute for a detailed material takeoff.
- Compare the result with the package yield, coverage, or weight listed by your supplier.
- Prices are user-entered estimates and may change by location, product, delivery, and season.
Accuracy and limitations
Calculapedia provides educational planning estimates. It does not inspect your site, select products, guarantee quantities, or replace a contractor, engineer, architect, building official, or supplier. Confirm the final quantity and any safety or code requirements before buying or building.