Plywood Calculator
Calculate how many 4x8 plywood sheets you need for subfloor or sheathing from your area, with 10% waste and total cost.
How this calculator works
A standard 4 ft x 8 ft plywood sheet covers 32 square feet. This calculator divides your total area — subfloor, wall sheathing, or roof deck — by that coverage figure and rounds up to a whole sheet.
Formula: Sheets = Area (sq ft) ÷ 32 sq ft per sheet, rounded up.
Worked example
A 24 ft x 20 ft area (480 sq ft):
- Area: 24 x 20 = 480 sq ft
- Sheets: 480 ÷ 32 = 15 sheets
- At $45/sheet, that’s 15 × 45 = $675.00 before waste.
Coverage reference
| Area | Sheets needed (32 sq ft/sheet) |
|---|---|
| 120 sq ft | 4 sheets |
| 480 sq ft | 15 sheets |
| 1,920 sq ft | 60 sheets |
How to measure your area
Measure the length and width of the floor, wall, or roof section being sheathed. For a whole-house subfloor, measure each room separately and add the totals, since irregular room shapes and hallways are easy to undercount when measured as one combined footprint.
Frequently asked questions
What size is a standard plywood sheet?
This calculator assumes the standard 4 ft x 8 ft plywood sheet, which covers 32 square feet. This size dominates residential framing, subflooring, and sheathing applications in the US.
What plywood thickness should I use for subfloor vs. wall sheathing?
Subfloor typically uses 3/4 in (23/32 in) tongue-and-groove plywood over joists spaced 16 in on-center, for stiffness underfoot. Wall sheathing is commonly 7/16 in to 1/2 in, since it's a structural skin rather than a walking surface. Roof sheathing usually falls in between at 1/2 in to 5/8 in depending on rafter spacing.
Plywood vs. OSB for subfloor — does the sheet count change?
No — both come in the same 4 ft x 8 ft sheet size, so the sheet count from this calculator applies to either material. The choice between them usually comes down to cost, moisture tolerance, and screw-holding strength rather than coverage.
How much waste should I add for plywood?
10% is standard for a rectangular room with a straightforward layout. Rooms with lots of jogs, closets, or non-rectangular shapes generate more cut-offs, so bump this up to 15% for complex floor plans.
Does this account for joists, screws, or construction adhesive?
No — this calculator counts plywood sheets only. Framing lumber, screws or nails, and construction adhesive (if used for a glued-and-screwed subfloor) are separate materials priced by linear foot or by box.
Estimates only. Verify quantities with your supplier before purchasing.