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 it’s calculated
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.
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.
Sources
- Sheets = area × (1 + waste) ÷ 32, rounded up; a 4 × 8-ft sheet = 32 sq ft (standard).