Plywood Calculator

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Calculate the number of plywood or OSB sheets needed for your project. Enter the total area to cover for subflooring, wall sheathing, roof decking, or any other application. Includes a waste factor for cuts and irregular shapes.

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Enter Your Measurements

Results

Sheets Needed (with waste)

11

sheets

Sheets (exact)

10

sheets

Total Area

320

sq ft

Area per Sheet

32

sq ft

Total Coverage Purchased

352

sq ft

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Formula

Sheets = (Area Length × Area Width) ÷ (Sheet Length × Sheet Width) × Waste Factor

How to Use This Calculator

How to Use

  1. 1

    Enter the length and width of the area to cover.

  2. 2

    Enter the plywood sheet dimensions (standard is 4 × 8 feet).

  3. 3

    Adjust the waste factor for cuts (10% for rectangular areas, 15-20% for complex shapes).

Frequently Asked Questions

Frequently Asked Questions

What thickness of plywood do I need?

For subflooring, use 3/4-inch plywood with 16-inch joist spacing or 7/8-inch with 24-inch spacing. Wall sheathing uses 7/16 to 1/2-inch OSB. Roof decking uses 1/2 to 5/8-inch plywood depending on rafter spacing.

What is the difference between plywood and OSB?

Plywood is made of cross-laminated wood veneers and resists moisture better. OSB (oriented strand board) is made of compressed wood strands and is less expensive. Both are structurally rated for the same applications.
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About This Calculator

This calculator uses the formula: Sheets = (Area Length × Area Width) ÷ (Sheet Length × Sheet Width) × Waste Factor. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.

Built and maintained by the CalcSmart team. Last updated March 2026.

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