Plywood Calculator
Find how many plywood sheets you need for floors or walls.
Plywood Calculator
What This Calculator Does
The Plywood Calculator tells you exactly how many 4x8 sheets of plywood or OSB you need for any project. Enter the total area to cover, select your waste factor, and the calculator returns the number of sheets needed - already accounting for waste.
Plywood and OSB are the standard sheathing materials for floors, walls, and roofs. A single 4x8 sheet covers 32 square feet. Ordering too few means mid-project trips to the lumber yard and potential delays. Ordering too many means tying up money in unused material. The built-in waste factor (5-15%) accounts for cuts around windows, doors, and irregular edges so your order matches your actual needs.
This calculator works for any sheathing project: subflooring, wall sheathing, roof decking, cabinet backs, or furniture-grade plywood projects. For wall-specific calculations including stud spacing, use our Framing Calculator.
How to Use
- Measure the total area to be covered in square feet. For walls: height x width minus window/door openings. For floors: length x width of the room.
- Enter the total area into the calculator field above.
- Select your waste factor: 5% for simple layouts, 10% for standard, or 15% for complex cuts.
- Click "Calculate" to see the number of 4x8 sheets needed.
- Round up to the nearest full sheet when ordering - partial sheets are not sold separately.
Reference Table
| Project Area | Sheets (4x8) | +10% Waste | Typical Use |
|---|---|---|---|
| 160 sq ft | 5 sheets | 6 sheets | Single room wall |
| 320 sq ft | 10 sheets | 11 sheets | Small room floor |
| 480 sq ft | 15 sheets | 17 sheets | One-car garage walls |
| 800 sq ft | 25 sheets | 28 sheets | Two-car garage floor |
| 1,600 sq ft | 50 sheets | 55 sheets | Average house subfloor |
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