Drywall Calculator
Use room mode for four walls and an optional ceiling, or enter surface areas directly. Sheet orientation and seam layout are not optimized by this estimate.
How to use this calculator
Choose room mode or direct-area mode.
Enter openings and select the sheet dimensions.
Set the allowance and use the rounded-up sheet quantity.
Formula
Net area = wall and ceiling area − openings. Sheets = ceil(net area × (1 + allowance) ÷ sheet area).
Worked example
A net 1,000 ft² area with 10% extra requires 1,100 ft². Using 4 ft × 8 ft sheets gives ceil(1,100 ÷ 32) = 35 sheets.
Assumptions and limits
- Default sheet size is 4 ft × 8 ft.
- Default extra material is 10%.
- Sheet layout, staggered joints, and local code requirements are excluded.
Sources
- National Institute of Standards and Technology: Circumference, Area and VolumeArea and volume formulas for common geometric shapes. Reviewed 2026-08-14.
- National Institute of Standards and Technology: Unit ConversionExact unit conversion and final-result rounding guidance. Reviewed 2026-08-14.
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Verification
How this calculator is checked
Trust comes from reproducible evidence, not model confidence. You can inspect the formula, assumptions, worked example, and cited sources on this page.
- Versioned calculationFormula logic is kept separate from the interface and covered by automated registry and behavior checks.
- Cited evidenceSources linked for independent checking: 2.
- Transparent AI useAI may assist drafting or adversarial review. Agreement between models is not proof, and no human expert review is claimed unless a named reviewer is shown.
Frequently asked questions
Should I subtract doors and windows?
Yes for a closer net-area estimate, although installers may retain some opening area as practical cutting allowance.
Can I use metric and US customary units in the Drywall Calculator?
Yes. Unit changes convert the same canonical measurement; they do not reinterpret or round your original value.
When does the calculator round?
The calculation keeps full precision internally and rounds only the displayed result. Whole packages are rounded up at the final step.
Last updated 2026-08-25 · 1.0.0 · 1.0.0 · Published by YunFanLabs