Plywood Calculator
Find out how many sheets of plywood you need to cover a floor, wall, or roof area based on your sheet size and a waste allowance.
What this calculator does
The plywood calculator finds how many full sheets of plywood you need to cover a subfloor, wall, or roof deck area.
The formula
Total area to cover is length times width. Standard plywood sheets are commonly sold in 4 ft x 8 ft sizes (32 square feet), but the calculator lets you enter any sheet size. Dividing the total area (plus a waste allowance for cuts and seams, typically 10%) by the area of one sheet, then rounding up, gives the number of full sheets to buy.
This estimate doesn’t account for cutting layout around joists, doors, or irregular shapes — always have a materials list confirmed against your actual framing plan before ordering.