Plywood Calculator
Plywood and OSB come in 4 × 8-foot sheets that each cover 32 square feet. Enter the area you're sheathing and this gives the number of sheets, with a waste allowance.
Sheets (4×8)
11sheets
How these numbers are worked out
The formula
Sheets = area × (1 + waste) ÷ 32, rounded up. A 4 × 8 sheet is 32 square feet. Add about 10% for cuts and offcuts — more for roofs and walls with lots of openings, where you trim more pieces.
Constants and sources
- Sheets = area × (1 + waste) ÷ 32, rounded up; a 4 × 8-ft sheet = 32 sq ft (standard).
How it was checked
Last reviewed . Before this calculator was published, its formula, constants and worked example were checked in a separate, AI-assisted review that redid the arithmetic and tested the factual claims; the site owner then approved it for publishing. No engineer or tradesperson reviews these pages. Where a figure depends on the product (a density, a coverage rate, a bag size), it is either an input you can change above or a fixed planning value stated on this page, so check it against your product's label or your supplier.
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Worked example
333 sq ft of subfloor with 10% waste: 333 × 1.10 = 366.3 ÷ 32 = 11.4 → 12 sheets (rounded up — you can't buy a partial sheet).
FAQs
- How many square feet is a sheet of plywood?
- A standard 4 × 8-foot sheet covers 32 square feet. Less common sizes (4 × 10, or 5 × 5 Baltic birch) cover different areas — divide by the right figure if you're using those.
- How much waste should I add?
- About 10% for a straightforward floor or wall; bump it to 15% for roofs, staircases, or rooms with lots of corners and openings where offcuts pile up.
- Does this work for OSB?
- Yes — OSB sheathing comes in the same 4 × 8-foot, 32-square-foot sheets, so the count is identical.