Drywall Calculator: Sheets, Screws & Mud
Enter your room size and openings. The calculator works out the wall and ceiling area, the number of drywall sheets, and roughly how many screws, feet of tape, and buckets of mud you need.
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How to calculate drywall
- Add the room length and width, multiply by 2, then by the ceiling height to get the wall area.
- Subtract about 21 sq ft per door and 15 sq ft per window.
- Add length × width if you are covering the ceiling.
- Add 10–15% for cuts and waste.
- Divide by 32 for 4×8 sheets or 48 for 4×12 sheets, and round up.
Sheets for common rooms (8 ft ceilings, walls + ceiling)
| Room | 4×8 sheets | 4×12 sheets |
|---|---|---|
| 10′ × 10′ | 14 | 9 |
| 12′ × 12′ | 17 | 12 |
| 12′ × 16′ | 21 | 14 |
With one door, one window, and 10% extra.
Questions
Drywall Calculator FAQ
Should I use 4×8 or 4×12 drywall sheets?
4×12 sheets mean fewer seams to tape, which saves finishing time, but they are heavy and hard to carry through tight spaces. 4×8 sheets are easier for DIY.
What thickness of drywall do I need?
1/2 inch is standard for walls. Ceilings often use 1/2 inch sag-resistant or 5/8 inch board, and garages attached to the house usually require 5/8 inch Type X fire-rated drywall.