Use this calculator for any job sheathed in full panels — plywood or OSB subfloors, wall sheathing, roof decking, shed floors or workbench tops. Enter the area and the sheet size to see how many sheets to buy.
Formula
Sheets = ⌈ Area × (1 + Waste) ÷ Sheet area ⌉
A standard 4 × 8 ft sheet covers 32 ft²; a 1220 × 2440 mm sheet covers 2.98 m².
Worked example
A 16 × 12 ft shed floor is 192 ft². With 10% extra that is 211 ft², or 7 sheets of 4 × 8 plywood.
Frequently asked questions
How many square feet does a sheet of plywood cover?
A standard 4 × 8 sheet covers 32 square feet.
Plywood or OSB for a subfloor?
Both are widely used. Tongue-and-groove plywood resists moisture swelling better at the edges; OSB is usually cheaper and very uniform.
Last updated · Calculations checked by automated tests· Editorial policy