Drywall Calculator
Estimate drywall for a room. Enter the dimensions and sheet size, choose whether to include the ceiling, and we'll size the sheets, joint compound, and screws.
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Drywall is sold in 4×8 or 4×12 sheets — larger sheets mean fewer seams to tape but are harder to handle. Plan roughly one box of joint compound (about 4.5 gallons) per 475 square feet for taping and three coats, and about one screw per square foot. Add 10% for waste and cuts around openings.
How it’s calculated
Area = walls (+ ceiling) × (1 + waste). Sheets = area ÷ sheet size; joint compound ≈ area ÷ 475 (4.5-gal boxes); screws ≈ 1 per sq ft.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Worked example
A 12x12 room with 8-ft walls plus ceiling needs ~19 4x8 sheets, ~2 boxes of compound, and ~530 screws.
Common mistakes
- Forgetting the ceiling, or skipping a waste allowance.
- Underbuying joint compound for taping and coats.
Where it is used
- Ordering drywall and supplies for a room.
- Choosing 4x8 versus 4x12 sheets.
Frequently asked questions
4×8 or 4×12 sheets?
Larger 4×12 sheets reduce the number of seams to finish but are heavier and awkward in tight spaces. Many DIYers prefer 4×8.
How much joint compound?
Roughly one 4.5-gallon box per 475 sq ft for tape plus three coats. Textured finishes use more.
Should I subtract doors and windows?
For small openings, leaving them in adds a useful buffer. For large openings, subtract their area to refine the count.
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