Drywall Calculator
Estimate drywall for a room or a whole project: number of sheets for walls and ceiling, plus joint compound, tape and screws, with door and window openings subtracted.
Drywall sheets
How to estimate drywall
- Enter the room length, width and wall height in feet.
- Enter the number of doors and windows; standard sizes are subtracted automatically.
- Choose the sheet size and whether to include the ceiling to see sheets, compound, tape and screws.
Drywall estimating tips
The calculator adds up the wall area (perimeter × height) and the ceiling, subtracts about 20 square feet per door and 15 per window, adds your waste allowance, and divides by the sheet size. Many pros do not subtract small openings at all, because the cutouts are usually waste anyway; a 10% allowance covers that either way.
Larger sheets mean fewer seams and less taping. 4 × 12 sheets on 8-foot walls hung horizontally can cover a 12-foot wall with no butt joints, but they are heavy and awkward on ceilings without a lift. Use 1/2-inch drywall for most walls, 5/8-inch for ceilings with wide joist spacing and where fire-rated board is required, and moisture-resistant board in bathrooms.
Finishing estimates use common rules of thumb: about 370 feet of tape, 140 pounds of ready-mix joint compound and 1,000 screws per 1,000 square feet of drywall. Actual use depends on the number of seams, corners and coats.
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Frequently asked questions
How many sheets of drywall for a 12 × 12 room?
With 8 ft walls, a ceiling, one door and one window, about 17 sheets of 4 × 8 including 10% waste.
How much joint compound do I need?
Roughly 140 lb of ready-mix (about two and a half 4.5-gallon buckets) per 1,000 sq ft for three coats.
How many screws per sheet of drywall?
About 28–32 for a 4 × 8 sheet on walls with 16-inch framing, more on ceilings.
What thickness should I use?
1/2 inch for most walls, 5/8 inch for ceilings and fire-rated assemblies, and moisture-resistant board in bathrooms.