3/4 plywood: actual thickness and weight
Sanded panel measures
0.734–0.766 in
18.64–19.46 mm
From the standard, NIST PS 1-22
A 4 × 8 ft sheet weighs about
73.6 lb
2.3 lb per square foot
One source: APA – The Engineered Wood Association, the trade association that publishes the panel design specification
How thick 3/4 plywood really is
3/4 is a Performance Category, the name stamped on the panel under the US plywood standard, NIST PS 1-22. The standard does not hold the panel to exactly 3/4 in; it gives a range. Sanded panels, the smooth faces sold for cabinets and furniture, are held to a tighter range than unsanded sheathing.
| Panel | Inches | Millimetres |
|---|---|---|
| Sanded | 0.734–0.766 | 18.64–19.46 |
| Unsanded, touch-sanded or overlaid | 0.719–0.781 | 18.26–19.84 |
Cutting a dado or rabbet for it? Measure the sheet you have: any panel inside the range meets the standard. Every category side by side is on the plywood thickness chart.
What a sheet of 3/4 plywood weighs
APA gives 2.3 lb per square foot as the approximate weight of 3/4 plywood for working out dead loads, and says to add 10% for OSB. A sheet is that weight times its area.
| Piece | Area | About |
|---|---|---|
| Full sheet, 4 × 8 ft | 32 sq ft | 73.6 lb |
| Half sheet, 4 × 4 ft | 16 sq ft | 36.8 lb |
| Quarter sheet, 2 × 4 ft | 8 sq ft | 18.4 lb |
| OSB of the same category, 4 × 8 ft (+10%) | 32 sq ft | 81 lb |
Species, glue and moisture move the real figure either way; hardwood-faced and MDF-core panels are not covered by APA’s table.
Span ratings made in 3/4
APA rated panels carry a span rating: the largest recommended center-to-center spacing of the supports under them, in inches, with the panel’s long side across three or more supports. On Rated Sheathing it is two numbers, roof/subfloor: a 32/16 panel may go over roof supports up to 32 in apart, or subfloor supports up to 16 in apart. On Rated Sturd-I-Floor, single-layer flooring, it is one support spacing (16 oc, 24 oc). These are the ratings APA lists in 3/4:
- Rated Sheathing 40/20
- Rated Sheathing 48/24
- Rated Sturd-I-Floor 24 oc
Next
Lay out parts on a sheet with the plywood cut list calculator. The face and back letters are explained on plywood grades, sheet sizes on plywood sizes, and the metric sheets on Baltic birch plywood. 3/4 MDF is sold at its full stated thickness; its weight is on its own page.
Work it out for your project
- Estimate the lumber for a whole project
List the parts, get the boards and board feet to buy, with waste.
Sources
- NIST (US Department of Commerce) / APA, Voluntary Product Standard PS 1-22, Structural Plywood, §5.4, §5.10 and Table 10 (effective 2 October 2023), read 2026-11-07
- APA – The Engineered Wood Association, Panel Design Specification, Form D510C (revised February 2008): §2.5 span ratings, Table 5 (thickness by span rating) and Table 6 (approximate weight), read 2026-11-08