Plywood Thickness Guide: Which Thickness Should You Use?
Plywood thickness affects stiffness, weight, screw-holding behavior, edge strength and cost. The “right” thickness depends on the load, support spacing and how the panel will be used.
Common thicknesses
Thin plywood is useful for backs, templates, drawer bottoms and lightweight panels. Mid-range sheets are common for cabinet parts and general shop projects. Thicker sheets are often chosen for work surfaces, structural assemblies or panels spanning larger distances.
Think about support spacing
A panel supported every few inches behaves differently from the same panel spanning several feet. When a project has significant loads or long spans, use a structural design reference or manufacturer's specifications rather than relying on a simple thickness rule.
Edge treatment matters
Plywood edges are less tolerant of some fasteners than solid wood. If the edge will be visible or heavily loaded, consider edge banding, solid-wood edging or a joinery method that spreads the load.
Calculate sheets, then verify the design
Use the Plywood Calculator to estimate quantity and cost. Then verify thickness, grade and structural suitability against your project requirements and the product data for the plywood you intend to buy.