Plywood Calculator
Estimate the exact number of plywood sheets required for your project. Whether you are sheathing a wall, subflooring a room, or decking a roof, this calculator accounts for sheet size, waste factor, and material grade.
Optional: Calculate total material cost
Sheet Area (4×8) = 32 sq ft
Sheet Area (4×10) = 40 sq ft
Waste Factor: 10% (walls), 12% (floors), 15% (roofs)
Total Cost = Sheets × Price per Sheet
Weight = Sheets × Sheet Area × Weight per sq ft
How many sheets of plywood do I need?
Divide your total square footage by 32 (area of a 4×8 sheet). For a 20×12 ft wall (240 sq ft): 240 ÷ 32 = 7.5, so you need 8 sheets. Always add 10-15% for waste, cutting errors, and offcuts that are too small to use. For roof sheathing, add 15% due to complex cuts around hips and valleys.
What is the most common plywood sheet size?
The standard plywood sheet size is 4ft × 8ft (32 square feet). Other common sizes include 4×10 (40 sq ft) for longer walls without horizontal seams, 5×5 (25 sq ft) for specialized applications, and 4×4 (16 sq ft) for smaller projects or easier handling.
What thickness of plywood should I use?
For wall sheathing: 1/2 inch or 5/8 inch. For roof sheathing: 5/8 inch or 3/4 inch. For subflooring: 3/4 inch tongue-and-groove. For cabinets: 1/2 inch for sides, 3/4 inch for shelves and doors. Thicker plywood provides more strength but adds significant weight and cost.
What is the difference between CDX and AC plywood?
CDX is a structural grade with C-grade face and D-grade back, designed for sheathing where appearance is not critical. AC grade has A-face (smooth, sanded) and C-back, suitable for visible applications like cabinets. Marine grade uses waterproof glue and has no voids, making it suitable for boats and outdoor use.
🔗 Related Calculators
📐 Formula
Sheet Area (4×8) = 32 sq ft
Sheet Area (4×10) = 40 sq ft
Waste Factor: 10% (walls), 12% (floors), 15% (roofs)
Total Cost = Sheets × Price per Sheet
Weight = Sheets × Sheet Area × Weight per sq ft