Plywood Sheet Calculator
Example: Surface area to cover: 800 sq ft · Area of one sheet: 32 sq ft · Cutting-waste allowance: 10 % · Price per sheet: 42 $
| Sheets to buy | 28 |
| Total sheet cost | $1,176 |
| Area including waste | 880 |
Worked example
To sheathe an 800 square foot surface with 4x8 sheets at 32 square feet each and a 10% cutting-waste allowance, the padded area is 880 square feet. Divide by 32 and round up: 28 sheets. At $42 a sheet that is $1,176. Because you cannot use every offcut, the waste allowance is what keeps you from ending the job one sheet short.
Frequently asked questions
Plywood or OSB, and does it change the count?
Both come in the same 4x8 sheet footprint, so the sheet count is identical; only the price and performance differ. OSB is usually cheaper, while plywood is lighter and handles moisture cycling better in some uses. Set the price to match whichever you buy.
How much waste should I allow for sheathing?
About 10% covers a straightforward rectangular deck, floor, or wall. Roofs with hips and valleys, and walls with many openings, generate more offcuts, so lean toward 15% there. Staggering seams and planning the layout on paper first reduces the real waste.
What thickness do I need?
Thickness depends on the use and the span between supports: subfloor is commonly 3/4 inch, wall sheathing often 7/16 to 1/2 inch, and roof sheathing typically 1/2 to 5/8 inch. Span rating on the panel stamp confirms it. Thickness does not change the sheet count, only the price and weight.
Should I account for the sheet orientation?
The area method here ignores orientation, which is fine for estimating. On the actual job, running sheets perpendicular to framing and staggering the joints affects how cleanly they lay out and how much you waste, so plan the layout when you order to stay close to the estimate.