Formula
The page rounds up:
sheets = ceil(area / sheet area)
A 4 by 8 sheet is 32 square feet. A 4 by 12 sheet is 48. Insulation batts are counted from a different face.
Assumptions
- The area is the surface you will cover.
- Every sheet is the size you select.
- A cut sheet is still ordered whole.
Worked example
480 square feet of 4 by 8 drywall is 15 sheets.
Input definitions
- Sheet area
- 32 square feet for 4 by 8, or 48 square feet for 4 by 12.
Limitations
Waste for openings you still sheet around, and the joint tape and compound, are not estimated.
Questions
Why 15 sheets?
480 divided by 32 is 15 exactly, so nothing extra is rounded up.
Should I subtract a door?
Only if you leave that opening out of the area you type. The page does not have a separate opening field.