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Drywall Calculator
Calculate drywall sheets, screws, joint compound, and material cost for any room
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Drywall Calculator
How to Calculate Drywall
Drywall is measured by the sheet. The most common size is 4×8 ft (32 sq ft per sheet), but larger sizes minimize seams and finishing work on taller walls and ceilings.
Drywall Sheet Formula
Wall Area = Perimeter × Height − (Doors × 21) − (Windows × 15)
Sheets = ⌈Wall Area × 1.10 ÷ Sheet Size⌉
Wall Area = Perimeter × Height − (Doors × 21) − (Windows × 15)
Sheets = ⌈Wall Area × 1.10 ÷ Sheet Size⌉
Drywall Thickness Reference
| Thickness | Weight/Sheet | Application |
|---|---|---|
| 1/4" | ~12 lbs | Curved surfaces, repairs over existing drywall |
| 3/8" | ~18 lbs | Repairs, lightweight applications |
| 1/2" | ~54 lbs | Standard walls and most ceilings |
| 5/8" | ~70 lbs | Ceilings, fire-rated walls, garages |
Installation Tips
- Hang ceiling drywall before walls — it supports the wall boards at the top
- Stagger vertical seams between rows so no seams line up from floor to ceiling
- Use a drywall lift for ceiling installation — it's worth the rental cost
- Score and snap cuts are faster than saw cuts for straight lines
- Apply three coats of joint compound (taping, topping, finish) with sanding between coats
? Frequently Asked Questions
How many drywall sheets do I need for a room?
Measure your total wall area (perimeter × ceiling height), subtract door and window openings, then divide by the sheet size. A 4×8 sheet covers 32 sq ft. Always add 10–15% for waste and cuts. Our calculator handles all of this automatically.
What thickness drywall should I use?
Standard walls and ceilings use 1/2" drywall. Ceilings often use 5/8" for sag resistance. Bathrooms should use moisture-resistant drywall (greenboard or cement board). Garages attached to the house require 5/8" Type X fire-rated drywall.
How many screws per sheet of drywall?
On walls, place screws every 16" in the field and every 8" on edges. This works out to roughly 30–35 screws per 4×8 sheet on walls, or about 60–70 screws per sheet on ceilings.
How much joint compound do I need?
A typical drywall job requires about 0.053 gallons of joint compound per sq ft of drywall. For a 1,000 sq ft area, you'd need roughly 53 gallons (or about four 5-gallon buckets) for all three coats combined.
What is the difference between 4×8, 4×9, and 4×12 sheets?
4×8 sheets are the most common and easiest to handle for one person. 4×9 sheets are ideal for 9-ft ceilings as they reduce horizontal seams. 4×12 sheets minimize seams on tall walls and ceilings but require two people to handle.
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💡 Pro Tips
Always add 10% extra to material estimates to account for waste, cuts, and mistakes.