Drywall Room Calculator
Calculate the total drywall sheets for an entire room — walls and ceiling — in one step. Enter your room length, width, and ceiling height, subtract door and window openings, and get an accurate sheet count with waste factored in.
How to use this calculator
- Enter your room length, width, and ceiling height in feet.
- Enter the number of doors and windows — the calculator deducts standard opening sizes.
- Check or uncheck include ceiling depending on your project scope.
- Adjust the waste factor and read your sheet count and cost estimate.
How we calculate this
Wall area is calculated as the perimeter (2 × (length + width)) × ceiling height. Ceiling area is length × width. Door openings subtract 21 sq ft each (3 ft × 7 ft standard); window openings subtract 15 sq ft each (3 ft × 5 ft standard). Total area is divided by sheet coverage (32 sq ft for 4×8), multiplied by (1 + waste factor), then rounded up to the nearest whole sheet.
What this calculator doesn't include
This calculator uses standard door (3×7 ft) and window (3×5 ft) opening sizes as approximations. Actual deductions will vary based on your specific opening dimensions. It does not account for knee walls, sloped ceilings, closets, or built-in niches. Joint compound, tape, screws, and corner bead are not included. For very complex rooms, add an extra 5% to the waste factor.
Example estimates — Drywall Room
Includes 10% waste. Cost estimate at ~$14/sheet (4×8, 1/2" standard) — adjust in the calculator above.
| Room Size | Surface Sq Ft | 4×8 Sheets | Est. Cost |
|---|---|---|---|
| 10×10 ft, 8 ft ceiling | 384 sq ft | 14 sheets | $196 |
| 12×10 ft, 8 ft ceiling | 436 sq ft | 15 sheets | $210 |
| 14×12 ft, 8 ft ceiling | 548 sq ft | 19 sheets | $266 |
| 16×12 ft, 8 ft ceiling | 604 sq ft | 21 sheets | $294 |
| 20×14 ft, 8 ft ceiling | 788 sq ft | 28 sheets | $392 |
| 20×16 ft, 9 ft ceiling | 932 sq ft | 33 sheets | $462 |
| 24×16 ft, 9 ft ceiling | 1,068 sq ft | 37 sheets | $518 |
| 10×10 ft, 8 ft ceiling (walls only) | 284 sq ft | 10 sheets | $140 |
| 14×12 ft, 8 ft ceiling (walls only) | 380 sq ft | 14 sheets | $196 |
| 20×14 ft, 9 ft ceiling (walls only) | 576 sq ft | 20 sheets | $280 |
Frequently asked questions
Add up all wall surface areas (perimeter × ceiling height) plus the ceiling area (length × width). Subtract approximate areas for each door (about 21 sq ft) and window (about 15 sq ft). Divide by 32 (for 4×8 sheets), add 10% waste, and round up. This calculator does all of that automatically.
Yes, but many pros only partially deduct — or skip deductions entirely for small windows — because the cut-off pieces can often be used elsewhere. A common rule: subtract full openings larger than 4 sq ft, ignore openings smaller than that. This calculator deducts standard door and window sizes as an approximation.
A 12×12 room with 8 ft ceilings needs approximately 15–17 sheets of 4×8 drywall including walls and ceiling, with 10% waste and one standard door. The exact count depends on window count and placement. Use this calculator with your specific dimensions for a precise answer.
Use moisture-resistant (MR) drywall — often called 'greenboard' — in bathrooms, laundry rooms, and other high-humidity areas. In shower and tub surrounds, use cement board (Durock, HardieBacker) or a dedicated tile backer board instead of any gypsum product. Standard drywall will absorb moisture and fail over time.
An experienced drywaller can hang a standard 12×12 bedroom in 2–4 hours. Taping, mudding, and finishing takes significantly longer — typically 3 coats of joint compound with drying time between coats, adding 2–4 days to the project. Plan for sanding and priming before painting.