Plywood and Sheet Goods Calculator

For subfloors, roof sheathing, soffits and shop projects: how many sheets cover your area.

Worked example

30 m² to cover with 4 x 8 ft sheets (2.97 m² each) and 10% waste: adjusted area = 33 m². Sheets = 33 / 2.97 = 11.1, rounded up to 12 sheets, which cover 35.7 m² in total.

How it works

Sheets = area x (1 + waste) / sheet coverage, rounded up. A standard 4 x 8 ft sheet covers 2.97 m². The waste allowance covers cuts, damaged corners and the unusable strips left at edges; rectangular rooms with full-sheet layouts need less, angled or cut-up spaces need more.

FAQ

Can I use offcuts to reduce the sheet count?

Often, yes for shop and subfloor work where joints can land on framing. This calculator assumes full coverage with simple cuts, so treat the count as the safe order quantity and expect a sheet or two of leftovers on simple jobs.

What thickness should I buy?

It depends on the job and the span: common choices are 12.5 mm (1/2 in) for roof sheathing, 15.5 to 19 mm (5/8 to 3/4 in) for subfloors, and 19 mm for shop cabinets. Span ratings are printed on the sheet; follow them and your local code.

Estimates only. This calculator gives planning estimates, not professional advice. Verify quantities and required thickness grades before ordering.