Drywall Calculator
Fill in the values and the answer updates as you type.
How the Drywall Calculator works
Wall area = perimeter × height − door and window openings. Add the ceiling if you are covering it. Divide by the area of one sheet (32 sq ft for 4×8, 48 sq ft for 4×12) and add 10% for cuts and mistakes. Joint compound is roughly 1 gallon per 100 sq ft.
Inputs and results
The Drywall Calculator takes 6 inputs and gives 4 results.
What you enter
- Room length (ft) — starts at 14.
- Room width (ft) — starts at 12.
- Wall height (ft) — starts at 8.
- Include the ceiling? — starts at Yes. Choose from: Yes and No.
- Sheet size — starts at 4 x 8 ft. Choose from: 4 x 8 ft and 4 x 12 ft.
- Doors and windows (total area) (sq ft) — starts at 40.
What you get
- Sheets needed (includes 10% waste)
- Surface area (sq ft)
- Wall area (sq ft)
- Joint compound (gallons, approx.)
Example: Drywall Calculator with the starting values
With room length 14 ft, room width 12 ft, wall height 8 ft, include the ceiling? Yes and sheet size 4 x 8 ft, the calculator returns:
| Sheets needed (includes 10% waste) | 19 |
|---|---|
| Surface area (sq ft) | 544 |
| Wall area (sq ft) | 376 |
| Joint compound (gallons, approx.) | 5.4 |
Change any value above and the results update straight away.
Drywall Calculator FAQ
How do I use the Drywall Calculator?
Enter room length, room width, wall height and include the ceiling? in the fields, then read sheets needed (includes 10% waste), surface area (sq ft), wall area (sq ft) and joint compound (gallons, approx.) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Drywall Calculator calculate?
Estimate drywall sheets and joint compound for a room. It returns sheets needed (includes 10% waste), surface area (sq ft), wall area (sq ft) and joint compound (gallons, approx.) from the 6 values you provide.
What values does the Drywall Calculator start with?
It opens with room length 14 ft, room width 12 ft, wall height 8 ft and include the ceiling? Yes so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Drywall Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Drywall Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.