Drywall Calculator
Calculate how many sheets of drywall you need for any room — walls and ceiling — in 4×8, 4×10 or 4×12 sheets.
A 12×12 ft room with 8 ft ceilings needs about 11 sheets of 4×8 drywall for the walls (12 with 10% waste).
How to Use This Drywall Calculator
- Enter the room length, width and ceiling height in feet.
- Subtract doors and windows (the calculator applies standard sizes if you leave them out).
- Choose the sheet size — 4×8 is the standard; 4×12 reduces joints on long walls.
- Tick the ceiling if you are hanging it too.
- Read the sheet count with a 10% waste allowance.
The Formula
Wall area = perimeter × height, minus openings. Sheets = area ÷ sheet area, rounded up. A 4×8 sheet covers 32 sq ft; 4×10 covers 40; 4×12 covers 48.
Walls = (2L + 2W) × HWall area in square feetSheets = ceil(area ÷ sheet area)4×8 = 32 ft² · 4×10 = 40 ft² · 4×12 = 48 ft²Total = sheets × 1.1010% waste for cutsScrews ≈ 250 per sheetValor editorial de referencia (no afecta el cálculo)Worked Example: 12×12 Room
A 12×12 ft room with 8 ft ceilings: perimeter 48 ft × 8 ft = 384 sq ft, minus one door (21) and one window (15) = 348 sq ft. 348 ÷ 32 = 10.9 → 11 sheets of 4×8, or 12 with 10% waste. Add the ceiling (144 sq ft) and you need 16 sheets, 17 with waste.
Sheets Needed by Room Size
| Room size | 4×8 sheets (walls) | with 10% waste | Walls + ceiling |
|---|---|---|---|
| 10 × 10 ft | 9 | 10 | 14 |
| 12 × 12 ft | 11 | 12 | 17 |
| 12 × 14 ft | 12 | 14 | 19 |
| 14 × 16 ft | 14 | 16 | 24 |
8 ft ceilings, one door + one window (36 sq ft). Ceiling column includes the 10% waste.
Sheet Sizes and Types
4×8 ft is the standard drywall sheet (32 sq ft). On long walls, 4×12 sheets mean fewer joints to tape and finish. Use regular drywall indoors, moisture-resistant (green board) in bathrooms, and fire-rated (Type X) in garages and shared walls. For hanging, plan on roughly 250 screws per sheet.
Quick Tips
- Hang sheets horizontally on walls to reduce joint length.
- Stagger the joints between rows for a stronger wall.
- Keep seams at least 6 in away from door and window corners.
Frequently Asked Questions
How many sheets of drywall do I need for a 12×12 room?
11 sheets of 4×8 for the walls (12 with 10% waste); 16 if you also cover the ceiling (17 with waste).
How big is a sheet of drywall?
The standard is 4×8 ft (32 sq ft). 4×10 (40 sq ft) and 4×12 (48 sq ft) are available for fewer joints.
How many screws per sheet of drywall?
About 250 screws per 4×8 sheet, spaced about 12 in apart on the studs.
How much drywall mud do I need?
Roughly 1 gallon of joint compound covers about 60–80 linear feet of taped joint — depends on the number of coats and finish level.