Short answer: A 12 ft by 14 ft room with 8 ft walls needs about 13 sheets of 4 by 8 drywall for the walls, with 10% waste, one door and two windows. Adding the ceiling brings it to about 19 sheets.
| Room size | Walls only | Walls and ceiling |
|---|---|---|
| 10 x 10 ft | 10 | 13 |
| 10 x 12 ft | 11 | 15 |
| 12 x 12 ft | 12 | 17 |
| 12 x 14 ft | 13 | 19 |
| 14 x 16 ft | 15 | 23 |
How it is calculated
Multiply the room perimeter by the wall height, subtract doors and windows, and add the ceiling area if you are hanging it. Divide by 32, the area of a 4 by 8 foot sheet, add about 10% for cuts, and round up.
Other supplies
Plan on about one screw per square foot of board, joint tape along every seam and a bucket or two of joint compound for a room. The calculator includes these quantities.
Worked example
A room 12 ft by 14 ft with 8 ft walls has 416 sq ft of wall. One door and two windows remove 51 sq ft, leaving 365 sq ft. With 10% extra that is 401.5 sq ft, which divided by 32 gives 13 sheets.
Use the Drywall CalculatorEnter your own measurements and get an exact amount.
Frequently asked questions
How many sheets of drywall do I need for a 12x12 room?
About 12 sheets for the walls only, and 17 once the ceiling is included. See the chart above.
Should I use 4x12 sheets instead of 4x8?
Longer sheets mean fewer seams and can be easier to finish, but they are harder to carry. Use 48 sq ft per sheet in the calculator if you choose them.
How much waste should I allow for drywall?
About 10%. Rooms with many corners, windows and angles need more.
Related calculators
Figures are typical planning values. Material sizes, densities and local requirements vary, so confirm with your supplier before ordering.
Last updated October 11, 2026.