Actual Thickness of of Plywood

Plywood is often sold in 1/4", 1/2", or 3/4" nominal thicknesses, but the actual thickness is often 1/32" thinner. Because the actual thickness may vary, measuring the plywood sheet using a caliper is the only accurate way to determine its thickness.

NOMINAL SIZE REFERENCE

• 3/4" sheet actually 23/32" thick... Caliper shows between 0.688 - 0.719
• 5/8" sheet actually 19/32" think ... Caliper shows between 0.565 - 0.594
• 1/2" sheet actually 15/32" thick... Caliper shows between 0.440 - 0.469
• 3/8" sheet actually 11/32" think... Caliper shows between 0.315 - 0.344
• 1/4" sheet actually 7/32" thick... Caliper shows between 0.200 - 0.219

The exception to this rule is plywood sheets that are over an inch thick. 1-1/4" and 1-1/8" plywood sheets are generally true sizes and not nominal.

Wood shrinks as it dries and moisture leaves the wood. This means that a sheet of plywood that started at 3/4” may shrink slightly after manufacturing. The glue between the plies will swell the wood slightly during manufacturing; it will then shrink as it dries. Plywood is almost always thinner than the nominal measurement due to the fact that most tooling in furniture and cabinet factories and manufacturing facilities can accommodate plywood that is thinner than expected but not thicker than expected.

Low cost 1/2" plywood now listed as 15/32 in. x 4 ft. x 8 ft. 3-Ply RTD Sheathing at common home repair stores. Plywood that is not sanded may be referred to as sheathing and is often referred to as 15/32" thick as to reflect the manufacturer’s tolerance of 1/32 inch, even though in layman’s terms the sheet is equivalent to a 1/2" sheet of plywood.