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Drywall Calculator

Whether you're finishing a basement, remodeling a room, or repairing water damage, this calculator tells you exactly how many sheets of drywall to buy plus the joint compound and tape to finish the job.

Enter Your Measurements

Results

Enter your measurements to see results

How to Use This Calculator

  1. Enter room length and width in feet.
  2. Enter wall height (usually 8 or 9 feet).
  3. Choose whether to include the ceiling.
  4. Select your drywall sheet size.
  5. Review the material estimates.

How Drywall Calculation Works

This calculator computes total wall area (and ceiling if selected), adds 10% for waste and cuts, then divides by the sheet size to get the number of sheets. Joint compound and tape estimates follow industry rules of thumb. For rooms with many doors and windows, you may need slightly less, but it's better to have extra than run short mid-job.

Formula

Wall area = 2 × (Length + Width) × Height. Ceiling area = Length × Width (if included). Sheets = ceil(Total area ÷ Sheet size × 1.10 for waste). Joint compound ≈ 0.053 gallons per sq ft. Tape ≈ 1 foot per sq ft of drywall.

Frequently Asked Questions

What thickness drywall should I use?
1/2 inch is standard for walls. 5/8 inch is required on ceilings (it resists sagging) and on walls/ceilings in attached garages (fire code). 1/4 inch is used for curved surfaces. Moisture-resistant (green board) or mold-resistant (purple board) is recommended for bathrooms.
How many sheets of drywall for a 12×12 room?
A 12×12 room with 8-foot ceilings needs about 12 sheets of 4×8 drywall for the walls, plus 5–6 sheets for the ceiling. With 10% waste, plan on 18–20 sheets total.
Should I use 4×8 or 4×12 drywall?
4×12 sheets mean fewer seams on longer walls, which reduces taping and finishing work. They're harder to handle — you'll likely need a helper. 4×8 is easier for DIY. Use 4×12 if you can manage the weight.

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