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Drywall Calculator
How many 4×8 drywall sheets for your walls and ceiling? Includes 10% waste for cuts.
Room measurements
One 4×8 sheet = 32 sq ft. 10% waste included for cuts and mistakes.
How to calculate drywall by hand
- Wall area = 2 × (length + width) × ceiling height.
- Add ceiling = length × width (if drywalling it).
- Divide total by 32 (one 4×8 sheet), add 10% waste, round up.
Example: 12×12 room, 8 ft ceilings → walls 384 + ceiling 144 = 528 sq ft → ÷32 = 16.5 → +10% = 19 sheets.
Drywall FAQs
How many square feet does a 4×8 sheet cover?
32 square feet. (4×12 sheets cover 48 sq ft — fewer seams, but harder to handle solo.)
What thickness of drywall should I use?
1/2 inch is standard for walls and ceilings. Use 5/8 inch for fire-rated walls (garages) and ceilings with 24-inch joist spacing to prevent sagging.
How many screws per drywall sheet?
About 32 screws per 4×8 sheet — roughly one every 12 inches on studs, 7 inches on ceiling joists.
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Frequently asked questions
What size do drywall sheets come in?
The standard sheet is 4x8 feet (32 square feet). Longer 4x10 and 4x12 sheets are available and mean fewer seams on big walls.
Should I use 1/2 inch or 5/8 inch drywall?
Use 1/2 inch for most walls. Ceilings and garages often require 5/8 inch Type X for fire code and to prevent sagging between joists.
How much extra drywall should I order for waste?
Order 10 percent extra to cover cuts around doors, windows and outlets. Complex rooms with many angles may need 15 percent.
How many screws does each drywall sheet need?
Plan on about 32 screws per 4x8 sheet: every 12 inches on ceilings and every 16 inches on walls, along each stud.