Drywall Calculator
Enter your area, openings, and any code checks. We will draft a material list.
Code notes follow the 2021 IRC. Local codes amend it, so check your local code.
Code checks
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Drywall FAQ
How much drywall do I need?
Add the wall and ceiling square footage, subtract openings, then divide by the sheet size and add a waste factor. Most jobs use about 10 percent waste on a clean rectangle, more on cut-up rooms.
When do I use 4x12 instead of 4x8?
Longer sheets mean fewer butt joints, which means less taping and a flatter wall. Use 4x10 or 4x12 on long walls and ceilings if you can carry them in and around corners. Stick with 4x8 in tight spaces.
1/2 inch or 5/8 inch?
Use 1/2 inch for typical walls and ceilings at 16 inch on center. Use 5/8 inch or sag-resistant board on ceilings at 24 inch on center or under spray texture, and 5/8 inch Type X on garage-to-living-space assemblies as required by IRC R302.6.
Assumptions and sources
- Joint compound: about 0.01 gal per sq ft for a 3-coat finish (USG, roughly 10 gal per 1,000 sq ft). Sold in 4.5 gal buckets.
- Tape: about 0.4 lf per sq ft (one foot covers 2 to 3 sq ft). Sold in 250 ft rolls.
- Screws: about 32 per 4x8 sheet at 16 in on center, about 245 per lb for 1-1/4 in #6. Ceilings use more.
- Weight: 1.6 lb per sq ft for 1/2 in board (USG). 5/8 in Type X is heavier.
- Openings: 21 sq ft per door, 12 sq ft per window, subtracted from the area.
- Corner bead: 8 ft sticks, rounded up from the linear feet you enter.
- Waste: your waste percent (default 10) is applied to sheets, compound, tape, and weight.
- Code checks follow the 2021 IRC: garage Type X (R302.6), wet-area backer (R702.4.2), ceiling sag under water-based texture or 24 in on center (R702.3.5). Local codes amend it, so check yours.
These are drafts to plan from. Saw kerf, odd layouts, and local code can change the count, so confirm before you order.