How it works
How to calculate it
The calculator applies the values you enter to this formula:
Sheets = ((wall area + ceiling area − openings) × (1 + waste rate)) ÷ 32.
How to use this calculator
- Measure four walls and ceiling area.
- Subtract major openings.
- Enter waste and the price of a standard 4 × 8 sheet.
Worked example
A 20 × 15 ft room with 8 ft walls and one typical door plus windows needs about 34 standard sheets including waste.
Important assumptions
- Includes four walls and the ceiling.
- Uses 4 × 8 ft sheets.
- Joint compound, fasteners, specialty board, and labor are excluded.
Common mistakes to avoid
- Leaving out the ceiling.
- Using the wrong panel size or thickness.
- Assuming offcuts will fit every remaining opening.
Method reviewed June 10, 2026. Prices and rates are user-provided defaults and should be replaced with local values.