How many sheets of plywood do I need?

Divide the total area in square feet by 32 (the area of a standard 4x8 sheet), then multiply by 1.10 to add a 10% waste factor for cuts. For example, a 320 sq ft floor needs (320 x 1.10) / 32 = 11 sheets. Complex layouts with many cuts may need 15% waste instead of 10%.

What thickness plywood for subfloor?

Use 3/4-inch (23/32") tongue-and-groove plywood for subflooring over joists spaced 16 inches on center. For 24-inch joist spacing, use 7/8-inch or 1-1/8-inch panels. The panels should be APA-rated Sturd-I-Floor or equivalent. Glue and screw for a squeak-free floor.

What is the difference between CDX and BCX plywood?

CDX has a C-grade face (tight knots, small splits allowed), D-grade back (larger knots and defects allowed), and exterior-rated glue (X). It is the standard for roof and wall sheathing. BCX has a B-grade face (smooth, patched) and C-grade back, making it suitable for cabinetry backs and underlayment where one smooth face is needed.

How much does a sheet of plywood cost?

Standard 4x8 CDX plywood costs approximately: 1/4" = $15-22, 3/8" = $22-30, 1/2" = $30-42, 3/4" = $45-60. Prices vary by region and market conditions. Specialty panels cost more: 3/4" Baltic birch runs $60-90, marine grade $70-120, and hardwood veneer panels $50-100+ per sheet.

Can I use OSB instead of plywood?

Yes, for most structural sheathing applications (roof, walls, subfloor), OSB is code-approved and costs 20-30% less than plywood. However, OSB swells more when wet and is slower to dry. For cabinetry, furniture, and visible applications, plywood is preferred for its smoother surface, better screw-holding, and superior moisture resistance.

How do I cut plywood without splintering?

Use a fine-tooth blade (80+ teeth for table saw, 60+ teeth for circular saw). Score the cut line with a utility knife before cutting. Place the good face down when cutting with a circular saw (blade cuts upward), or good face up on a table saw (blade cuts downward). Use painter's tape along the cut line to further reduce tear-out.

Plywood Calculator

How many plywood sheets do I need? Free calculator for 6 mm to 18 mm panels — gives sheet count and cost estimate in £.

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Enter Your Measurements

How to Use This Calculator

1Enter the length and width of the area to cover in feet.
2Select the plywood thickness from the dropdown.
3Click Calculate to see sheet count and cost estimate.

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About This Material

Plywood is an engineered wood panel made from thin layers (plies or veneers) of wood glued together with adjacent layers having their grain rotated 90 degrees. This cross-laminated construction gives plywood superior strength, stiffness, and dimensional stability compared to solid wood of the same thickness. Standard plywood sheets measure 4 feet by 8 feet (32 square feet) and are available in thicknesses from 1/4 inch to 3/4 inch. Common grades include CDX (construction grade, suitable for sheathing and subflooring), BC sanded (one smooth face for cabinetry and shelving), AC (one premium face), and marine grade (waterproof glue, no voids). Plywood is used extensively in residential construction for roof sheathing, wall sheathing, subflooring, cabinet boxes, furniture, and finish applications. For structural applications, use panels stamped with the APA (Engineered Wood Association) grade mark. The most common structural plywood is 1/2-inch CDX for wall sheathing and 3/4-inch tongue-and-groove for subflooring. Always store plywood flat and indoors — panels stored on edge or exposed to moisture will warp permanently. When cutting, use a fine-tooth blade (80-tooth for table saw) to minimize tear-out on the veneer face.

Next Steps:

Lumber Cost Calculator →Board Feet Calculator →OSB Panel Calculator →

Installation Tips

•Leave a 1/8-inch gap between sheets to allow for thermal expansion.
•Install with the face grain perpendicular to supports (joists or studs).
•Use 8d nails or #8 screws at 6" on center at edges, 12" in the field.
•Stagger joints between rows for maximum strength.

Common Mistakes to Avoid

Not leaving expansion gaps — tight-butted panels will buckle when they absorb moisture.
Installing sheets with grain parallel to supports instead of perpendicular.
Using interior-grade plywood in exterior or high-moisture applications.
Not staggering seams between courses, which creates a weak line.

Plywood Calculator

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About This Material

Installation Tips

Common Mistakes to Avoid

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