Drywall calculator
How many sheets of drywall a room needs for the walls and ceiling, in 4 × 8, 4 × 10 or 4 × 12 ft sheets.
Drywall sheets
- Walls
- Ceiling
Doors are counted as 21 sq ft and windows as 15 sq ft.
How to use it
Enter the room's length, width and wall height in feet, how many doors and windows it has, and whether you're covering the ceiling too. Pick the sheet size you'll buy. The calculator works out the area to cover and the number of sheets, with extra for cuts.
How it's calculated
- Wall area = 2 × (length + width) × height.
- Subtract 21 sq ft per door and 15 sq ft per window.
- Add the ceiling (length × width) if you're including it.
- Sheets = total area × (1 + extra) ÷ sheet area, rounded up.
| Sheet size | Area |
|---|---|
| 4 × 8 ft | 32 sq ft |
| 4 × 10 ft | 40 sq ft |
| 4 × 12 ft | 48 sq ft |
Which sheet size?
- 4 × 8 ft sheets are the easiest to carry, fit in most vehicles, and are the only practical choice for one person working alone.
- 4 × 12 ft sheets cover a typical wall with fewer seams, which means less taping and mudding, but they're heavy and need two people.
- Match sheet length to the wall where you can. A 12 ft wall covered with 12 ft sheets has no butt joints at all.
Tips
- Many pros don't subtract small windows. The offcuts rarely fit anywhere else. If you're unsure, set windows to 0 for a little extra margin.
- Ceilings first, then walls. The wall sheets then help hold up the edges of the ceiling sheets.
- Check the thickness. 1/2 in is standard for walls; ceilings and fire-rated areas often call for 5/8 in. Local codes decide what's required, for example between a garage and living space.