Drywall Calculator
Free drywall calculator. Enter room size to get the number of 4 × 8, 4 × 10 or 4 × 12 drywall sheets, plus joint compound, tape and screws.
- Sheets
- 17
- 4 × 8 ft
- Drywall area
- 492 sq ft
- walls 384 + ceiling 144
- Joint compound
- 2 buckets
- 4.5 gal premixed
- Sheet cost
- $255
Finishing supplies
| Paper joint tapeAbout 370 ft per 1,000 sq ft | 190 ft |
| Drywall screwsAbout 32 per sheet | 544 |
| Joint compoundAbout 1 bucket per 400 sq ft, three coats | 2 buckets |
Price
$255
Sheets only, before mud, tape, screws and tax
Default prices are typical U.S. retail figures, reviewed November 2026. Enter your supplier's prices for an exact total.
Drywall is sold in 4 foot wide sheets, usually 8, 10 or 12 feet long. Longer sheets mean fewer joints to tape and finish, but they are heavier to carry and lift.
Enter the room size, choose whether to include the ceiling, and subtract doors and windows. The calculator gives you the number of sheets plus rough quantities of joint compound, tape and screws.
How to use the drywall calculator
- Add up the room's wall lengths and multiply by the wall height.
- Add the ceiling area (length × width) if you're hanging the ceiling too.
- Subtract about 21 sq ft per door and 15 sq ft per window.
- Add 10% for waste and divide by the sheet area (32 sq ft for 4 × 8).
Area = 2 × (length + width) × height + ceiling − openings. Sheets = area × 1.10 ÷ sheet area. Mud ≈ 1 bucket per 400 sq ft; tape ≈ 370 ft per 1,000 sq ft.
Drywall sheets by room size
8 ft walls plus ceiling, one door and one window, 10% waste.
| Room | 4 × 8 sheets | 4 × 12 sheets |
|---|---|---|
| 10 × 10 ft | 14 | 9 |
| 12 × 12 ft | 17 | 12 |
| 12 × 14 ft | 19 | 13 |
| 14 × 16 ft | 23 | 16 |
| 20 × 20 ft | 35 | 24 |
Tips before you buy
- Hang ceilings first, then walls, with wall sheets horizontal to reduce joints.
- Use 5/8 in Type X on garage walls and ceilings shared with the house; check your local code.
- Use moisture-resistant board in bathrooms and cement board behind tile in showers.
- Mud and tape quantities vary a lot with skill and finish level; buy a little extra and return unopened buckets.
Frequently asked questions
How many sheets of drywall do I need for a 12x12 room?
With 8 foot walls, the ceiling, one door and one window, a 12 × 12 room needs about 17 sheets of 4 × 8 drywall including 10% waste, or 12 sheets of 4 × 12.
How much joint compound do I need?
Plan on roughly one 4.5 gallon bucket of premixed compound per 400 square feet of drywall for a standard three-coat finish. A 12 × 12 room with a ceiling needs about two buckets.
How many screws per sheet of drywall?
About 32 screws for a 4 × 8 sheet: screws every 12 inches on ceilings and every 16 inches on walls, along each stud or joist.
Should I use 4x8 or 4x12 drywall sheets?
4 × 12 sheets leave fewer seams, which saves taping time and gives a better finish. 4 × 8 sheets are easier to carry up stairs and handle alone.