How to Estimate Drywall or Sheetrock
You can both estimate the total square feet of drywall, also known as gypsum board, you’ll need and the number of sheets. For an estimate, use the calculator above or follow these steps:
Drywall needed = total area/sheet size.
- Multiply the length and height of one wall.
- Don’t worry about excluding windows and doors, they’ll get trimmed later.
- Record the area.
- Repeat this process for all walls.
- Don’t forget to measure each side of a wall that needs covering.
- Multiply the length times the width of each ceiling area and combine them.
- Measure the floor directly below the ceiling area.
- Add together all wall and ceiling areas.
- This is the total square feet of your project.
- Divide this number by the square feet of each drywall sheet
Sheet Size | Square Feet |
---|---|
4×8 | 32 |
4×9 | 36 |
4×10 | 40 |
4×12 | 48 |
4×16 | 64 |
How much does it cost to drywall a 12×12 room?
Cost To Hang And Finish Drywall
The average cost to hang and finish drywall in a standard 12′ x 12′ room is $872. *Expect to pay an extra 15%–20% on labor if a contractor oversees the project.
Should you hang drywall vertically or horizontally?
Should drywall touch the floor?
Do you put flooring down before drywall?
Measure Doors and Windows
Apply the tape measure to any doors or windows in the wall so you can later subtract these measurements from the overall square footage of the wall. Write these measurements down.

Determine the Ceiling’s Square Footage
Use the tape measure to calculate the width and length of the floor area, which will be the same as the ceiling area if you have a flat ceiling. If you have a sloped ceiling where you plan to install drywall, use the ladder to access and determine the height and width measurements. Write these measurements down.
Add Your Measurements Together
Add the square footage of the walls and ceiling to get the total square footage of drywall required. For instance, our example room has four walls that equate to 128 square feet for each of four flat surfaces. A flat ceiling would total 256 square feet, as it is 16 by 16 feet. Multiply the wall square footage by four and add the total square footage for the ceiling to a total of 768 square feet.
If one wall had a 6-by-4-foot window and a door 3 feet wide and 6 feet 8 inches tall, subtract these measurements from the overall square footage. To make the door measurement easier to calculate, round up to 7 feet tall. Subtract the door area, 21 feet, and the window area, 24 feet, from the overall 768 square footage to arrive at a total of 723 square feet needed in drywall coverage.
Example of estimating drywall for a single room
15′ by 15′ room with 8’ceilings | |
---|---|
Wall A | 15’x8’=120ft2 |
Wall B | 15’x8’=120ft2 |
Wall C | 15’x8’=120ft2 |
Wall D | 15’x8’=120ft2 |
Ceiling | 15’x15’=225ft2 |
Total Square Footage | 705ft2 |
