Drywall Calculator
for Sheets, Mud and Screws
Enter your room size and sheet size. See how many sheets to order, plus the screws, joint compound and tape to finish them.
4×8, 4×10 and 4×12 · Screws, mud and tape · Works on your phone
Estimates only. Your numbers stay in your browser and aren't saved or sent anywhere.
How to calculate drywall
Wall area = 2 × (length + width) × height
Ceiling area = length × width
Sheets = (wall + ceiling area) × (1 + waste %) ÷ sheet coverage
For example, a 12' by 12' room with 8' walls has 384 sq ft of wall and 144 sq ft of ceiling, or 528 sq ft in total. With 12% waste, that's 19 sheets of 4×8.
The calculator doesn't subtract doors and windows. Most drywallers leave them in, because a lot of what's cut out ends up as waste anyway, and it gives you some spare board.
How much screws, mud and tape to buy
The rules of thumb the calculator uses, for a standard three-coat finish:
| Material | Rule of thumb |
|---|---|
| Screws | About 1 lb per 200 sq ft |
| Joint compound | About 1 gallon per 100 sq ft |
| Paper tape | About 1 250 ft roll per 550 sq ft |
These vary with how your framing is spaced, how the board is laid out and how heavily you finish, so treat them as a starting point.
Which sheet size to use
Longer sheets mean fewer butt joints, which means less taping and a better finish. A 4×12 is common on long walls and ceilings if you have the crew and the access to get it in. A 4×8 is easier to handle, especially when you're working alone or in tight spaces.
Which thickness to use
1/2" is standard for walls and most ceilings. 5/8" is used on ceilings with framing 24" on center, and 5/8" Type X where a fire rating is required, such as between a garage and a house. Check your local code.
Questions
- With 8' walls and the ceiling, that's 528 sq ft. With 12% waste, it comes to 19 sheets of 4×8.
- 10% to 15% is typical. Rooms with lots of corners, angles or openings need more, and simple rectangular rooms need less.
- About 32 for a 4×8 sheet on walls with framing 16" on center. Ceilings and 24" framing can change that, so check your local code.
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