Drywall Calculator

Estimate the drywall sheets and finishing materials needed for walls and ceilings. Enter areas and deductions to get sheets, compound, tape, and screws.

Walls
Ceiling

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Results

Enter your measurements to see an estimate.

Detailed breakdown

How to use the undefined

Enter the total run of walls and their height, plus the ceiling size if you are drywalling it. Subtract large openings with the deductions field (a standard door is about 20 sq ft). Set the sheet coverage (a 4×8 sheet is 32 sq ft) and a waste allowance. The tool estimates sheets, joint compound, tape, and screws.

Formula and methodology

Gross area = (wall length × wall height) + (ceiling length × ceiling width). Net = gross − deductions. Adjusted = net × (1 + waste%/100). Sheets = adjusted ÷ sheet coverage, rounded up. Compound ≈ 0.053 lb/sq ft, tape ≈ 0.75 ft/sq ft, screws ≈ 40 per sheet.

Worked example

Room: 40 ft of wall × 8 ft = 320 sq ft, ceiling 12×10 = 120 sq ft, 40 sq ft deductions, 10% waste, 32 sq ft sheets. Net = 400 sq ft, adjusted = 440 sq ft ÷ 32 = 14 sheets. Enter the values above to confirm.

Helpful measurement tips

  • Use 12 ft sheets on long walls to reduce butt joints where practical.
  • Finishing supplies vary with the number of coats — treat compound and tape as rough guides.
  • Ceilings often use thicker or sag-resistant board; check your span.

Frequently Asked Questions

How big is a standard drywall sheet?
The most common sheet is 4 by 8 feet (32 square feet). Longer 4 by 12 sheets reduce the number of joints on large walls.
How much joint compound will I need?
As a rough guide, about 0.05 pounds per square foot for a standard three-coat finish. Higher finish levels use more.
How many screws per sheet?
Roughly 32 to 40 screws per sheet, depending on framing spacing and whether it is a wall or ceiling.
Should I subtract doors and windows?
Subtract large openings for a tighter estimate, but keep some allowance since offcuts around openings are often unusable.
How much waste should I add?
About 10% covers cuts and damaged edges. Complex rooms with many openings may need more.
How accurate is this estimate?
It is a planning figure. Finishing materials in particular vary with technique and finish level, so verify before buying.
Disclaimer: Results are general estimates. Finishing material needs vary with technique and finish level. Verify your measurements before purchasing.