Plywood & Sheathing Calculator
Figure out exactly how many 4×8 sheets of plywood or OSB you need for wall sheathing, subfloor, or roof decking. Enter your area dimensions and get sheet counts with waste factor and cost estimates.
Enter Your Measurements
Full Breakdown
Total Area
Area + Waste
Sheet Coverage
Sheets Needed
Estimated Cost
How to Use This Calculator
- Choose your input method — enter length × height or total square feet.
- Select the sheet size (4×8 is standard; 4×10 and 4×12 for taller walls).
- Set the waste factor — 10% for simple rectangles, 15% for complex cuts.
- Enter cost per sheet for a budget estimate.
- Click "Calculate Sheets" to see how many you need.
The Formula
Total Area = Length × Height (or entered sq ft)
Area with Waste = Total Area × (1 + Waste%/100)
Sheets Needed = ⌈Area with Waste ÷ Sheet Area⌉
A standard 4×8 sheet covers 32 sq ft. Always round up — you can't buy partial sheets. Use 10% waste for rectangular areas, 15% for L-shapes or areas with many openings.