Construction Calculators
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Drywall Calculator
Calculate drywall sheets, joint tape, mud, and screws for any room. Supports multiple sheet sizes with automatic waste factor.
Drywall Sheets & Supplies Calculator
Calculate sheets, tape, joint compound, and screws with 10% waste factor
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How to Calculate Drywall
Calculating drywall requires measuring wall and ceiling areas, subtracting openings for doors and windows, then dividing by the sheet size. Always add 10% waste for cuts and fitting.
Step-by-Step
1. Calculate wall area: perimeter × ceiling height.
2. Subtract openings: each standard door = 21 ft², each window = 15 ft².
3. Add ceiling if needed: length × width.
4. Divide total area by sheet size (32 ft² for 4×8) and multiply by 1.10 for waste.
Sheet Size Guide
| Size | Area | Best For |
|---|---|---|
| 4′ × 8′ | 32 ft² | Standard ceilings (8′) |
| 4′ × 10′ | 40 ft² | Fewer seams, 9–10′ ceilings |
| 4′ × 12′ | 48 ft² | Commercial, long walls |
Finishing Supplies
Joint tape: 1 roll per 500 ft². Joint compound: one 4.5-gallon bucket per 480 ft² (three coats). Screws: about 32 per sheet, spaced 12" apart on edges and 16" in the field.
Frequently Asked Questions
How many sheets of drywall for a 12×12 room?
A 12×12 room with 8-foot ceilings has 384 ft² of wall area minus about 57 ft² for a door and window = 327 ft². With 10% waste: 360 ft² ÷ 32 = about 12 sheets (4×8). Add 5 for the ceiling (144 ft²).
How much does drywall cost per sheet?
Standard 4×8 drywall sheets cost $12–$18 each. Moisture-resistant (green board) costs $14–$22, and fire-rated (Type X) costs $15–$24. Installation runs $1.50–$3.00 per square foot.
Should I use 4x8 or 4x12 drywall?
Use 4×12 sheets for long walls and ceilings — they reduce the number of seams by 33%. Use 4×8 for standard rooms and areas with limited access where larger sheets are hard to maneuver.