🧱 Drywall Calculator
Calculate drywall sheets, joint compound, tape, and screws needed for walls and ceilings. Subtract doors and windows automatically.
~21 sq ft each
~15 sq ft each
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Wall Area
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sq ft
Total Area (with waste)
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sq ft
Sheets Needed
0
sheets
Joint Compound
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gallons
Screws Needed
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pcs
Estimated Cost
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USD
How to Calculate Drywall Needed
Accurately calculating drywall ensures you buy the right number of sheets and supplies for your project.
Drywall Calculation Formula
Wall Area = Perimeter × Ceiling Height
Net Area = Wall Area − Doors − Windows + Ceiling (optional)
Sheets = Net Area ÷ Sheet Size × (1 + Waste%)
Drywall Sheet Sizes Reference
| Size | Area | Weight (1/2") | Best For |
|---|---|---|---|
| 4×8 ft | 32 sq ft | 57 lbs | Standard walls, 8ft ceilings |
| 4×10 ft | 40 sq ft | 71 lbs | 9-10ft ceilings, fewer joints |
| 4×12 ft | 48 sq ft | 86 lbs | High ceilings, large walls |
| 4×8 ft (5/8") | 32 sq ft | 74 lbs | Ceilings, fire-rated walls |
Frequently Asked Questions
How many sheets of drywall do I need?
Calculate total wall area (perimeter × height), subtract doors (~21 sq ft each) and windows (~15 sq ft each), then divide by the sheet size (32 sq ft for 4×8). Add 10-15% for waste.
What size drywall should I use?
Standard is 4×8 ft (32 sq ft). For 9-10 ft ceilings, use 4×10 or 4×12 sheets to reduce joints. Use 1/2 inch thick for walls, 5/8 inch for ceilings and fire-rated walls.
How much joint compound do I need?
Plan for approximately one gallon per 100 sq ft of drywall. A standard 4.5-gallon bucket covers about 450 sq ft. You'll need 3 coats for finishing.
How many drywall screws do I need?
Use approximately 32 screws per 4×8 sheet (about 1 screw per sq ft). Place screws every 12 inches on edges and 16 inches in the field.
How much does drywall cost?
Standard 4×8 sheets cost $10-$15 each. Moisture-resistant costs $13-$20. Fire-rated (Type X) costs $12-$18 per sheet. Professional installation adds $1-$3 per sq ft for labor.
How many sheets for a 12×12 room?
A 12×12 room with 8ft ceilings has 384 sq ft of wall area. Subtracting a door and window (~36 sq ft), you need about 348 sq ft or 11 sheets of 4×8 drywall, plus 10% waste = 12 sheets.
Should I drywall ceiling or walls first?
Always hang ceiling drywall first, then walls. The wall sheets will butt up against and help support the ceiling panels at the edges, creating tighter, cleaner joints.
How much drywall tape do I need?
Estimate about 370 feet of tape per 1,000 sq ft of drywall. A standard 500-foot roll covers about 1,350 sq ft of drywall installation.