How this calculator works
A 4×8 ft sheet of plywood covers 32 sq ft. The calculator divides your area by 32 and adds 10% for cuts and waste.
Worked example — a 20 ft × 12 ft subfloor:
240 sq ft × 1.10 = 264 ÷ 32 = 9 sheets.
240 sq ft × 1.10 = 264 ÷ 32 = 9 sheets.
Subfloor, sheathing or roof?
The sheet math is the same for floors, walls and roofs — just enter the total area you’re covering. Thickness affects price, not sheet count.
Frequently asked questions
How many square feet in a sheet of plywood?
A standard 4×8 ft sheet covers 32 square feet.
How much extra plywood should I buy?
About 10% to cover offcuts and the occasional damaged sheet.