Plywood Thickness Chart — Inches & mm
Need a size fast? Find common thicknesses below, then select any category for its exact PS 1-22 permitted range.
Quick plywood thickness reference · Select a size for details · sanded PS 1 structural plywood
| Common retail name / category to check | Permitted thickness range |
|---|---|
| 1/4 → 1/4 category | 0.234–0.266 in5.95–6.75 mm |
| 3/8 → 3/8 category | 0.359–0.391 in9.13–9.92 mm |
| 1/2 → 15/32 category | 0.453–0.484 in11.51–12.30 mm |
| 5/8 → 19/32 category | 0.578–0.609 in14.68–15.48 mm |
| 3/4 → 23/32 category | 0.703–0.734 in17.86–18.65 mm |
Category matters: these are useful retail comparisons, not guaranteed dimensions. 15/32 and 1/2, or 23/32 and 3/4, remain separate PS 1-22 categories. Confirm the panel mark.
Popular sizes (common retail shorthand → selected category)
Complete PS 1-22 Table 10 — sanded structural plywood. Read minimum and maximum; the fraction is a category label, not a guaranteed actual measurement.
Table columns: PS 1 Performance Category, minimum thickness, and maximum thickness, each value in inches and millimeters.
| Perf. Cat. | Minimum | Maximum |
|---|---|---|
| 1/4 | 0.234 in5.95 mm | 0.266 in6.75 mm |
| 5/16 | 0.297 in7.54 mm | 0.328 in8.33 mm |
| 11/32 | 0.328 in8.33 mm | 0.359 in9.13 mm |
| 3/8 | 0.359 in9.13 mm | 0.391 in9.92 mm |
| 7/16 | 0.422 in10.72 mm | 0.453 in11.51 mm |
| 15/32 | 0.453 in11.51 mm | 0.484 in12.30 mm |
| 1/2 | 0.484 in12.30 mm | 0.516 in13.10 mm |
| 9/16 | 0.547 in13.89 mm | 0.578 in14.68 mm |
| 19/32 | 0.578 in14.68 mm | 0.609 in15.48 mm |
| 5/8 | 0.609 in15.48 mm | 0.641 in16.27 mm |
| 11/16 | 0.672 in17.07 mm | 0.703 in17.86 mm |
| 23/32 | 0.703 in17.86 mm | 0.734 in18.65 mm |
| 3/4 | 0.734 in18.65 mm | 0.766 in19.45 mm |
| 13/16 | 0.788 in20.02 mm | 0.837 in21.26 mm |
| 7/8 | 0.849 in21.56 mm | 0.901 in22.89 mm |
| 1 | 0.970 in24.64 mm | 1.030 in26.16 mm |
| 1-1/8 | 1.091 in27.72 mm | 1.159 in29.43 mm |
| 1-1/4 | 1.213 in30.80 mm | 1.288 in32.70 mm |
No Performance Categories match the search. Clear the search to show all 18 rows.
Source: DOC PS 1-22 Table 10. The standard’s SI values govern; inches are its published conversions. Dimensional measurements are referenced to 9% moisture content. This chart applies to PS 1 structural plywood, not every hardwood, Baltic birch, OSB, or imported panel.
Print view: all 18 PS 1-22 Performance Categories, with the currently selected finish group and source/measurement notes.
Nominal vs. Actual Plywood Thickness — Quick Reference
These are common shopping comparisons, not a universal manufacturing conversion. A store’s rounded nickname may point to a different printed Performance Category; select the actual mark in the chart above for its tolerance range.
| Commonly requested | Category often seen on sheathing | Fraction as decimal |
|---|---|---|
| 1/4 in | 1/4 (check product label) | 0.25000 in |
| 3/8 in | 11/32 or 3/8 | 0.34375 or 0.37500 in |
| 1/2 in | 15/32 or 1/2 | 0.46875 or 0.50000 in |
| 5/8 in | 19/32 or 5/8 | 0.59375 or 0.62500 in |
| 3/4 in | 23/32 or 3/4 | 0.71875 or 0.75000 in |
Retail naming varies by product. The fractional-decimal column converts the category names, not measured thickness. For example, a 23/32 category sanded PS 1 panel has a permitted range of 0.703–0.734 in, not one fixed value of 0.71875 in. APA’s construction guide lists adjacent 15/32 and 1/2, 19/32 and 5/8, and 23/32 and 3/4 categories side by side.
Find the Category for a Measured Plywood Thickness
Measured a sheet with calipers? Enter the result to see which PS 1-22 Table 10 ranges contain that value. Several categories can match when published tolerances overlap. This is not proof of a panel’s certification or stamp.
Enter a thickness and select Find matching categories.
Reverse lookup uses the same finish selection as the chart above. It compares your value against published rounded limits in the selected unit. The actual panel mark and the governing standard determine the panel’s identity.
Is 23/32 Plywood the Same as 3/4?
No—not as PS 1-22 category designations. Both can appear in conversations about roughly three-quarter-inch plywood, but Table 10 lists separate limits. Even a measured panel thickness cannot always distinguish the two.
23/32 Performance Category
0.703–0.734 in
17.86–18.65 mm · sandedUnsanded: 0.688–0.750 in
3/4 Performance Category
0.734–0.766 in
18.65–19.45 mm · sandedUnsanded: 0.719–0.781 in
The practical difference: their sanded ranges meet at 0.734 in, while unsanded ranges overlap from 0.719 to 0.750 in. A caliper reading alone may therefore not tell you which category is stamped on the sheet.
How to Measure Actual Plywood Thickness
- Check the stamp, grade, and governing standard. Confirm you have PS 1 structural plywood before applying these ranges.
- For cabinet joinery or dado fit: use calipers on the actual sheet and check several clean spots rather than relying on the printed fraction.
- For PS 1-22 conformity testing: §5.10.2 specifies a micrometer, controlled contact pressure, representative readings near mid-length of all four edges, and the four-measurement average.
PS 1-22 measurement requirements include 19.1 mm (3/4 in) anvils and 34–69 kPa (5–10 psi) pressure; see the standard for all details. A shop caliper reading is useful for fit but does not replace the formal conformance method.
Sanded vs. Unsanded Plywood: Why Ranges Differ
For PS 1-22 Table 10, sanded Performance Categories of 3/4 and smaller use tighter tolerance limits than unsanded, touch-sanded, and overlaid panels. For bigger categories, percentage-based tolerances apply. Changing finish in the chart updates both published minimum and maximum limits—not a single nominal-to-actual conversion.
What About Cabinet Plywood, Baltic Birch and 18 mm Sheets?
Do not use structural-plywood tolerance ranges for every plywood product. ANSI/HPVA HP-1-2024 governs many hardwood and decorative plywood products using a separate Thickness Class approach. Imported plywood, Baltic birch, and metric-labeled sheets should be checked against the manufacturer’s declared actual dimensions.
18 mm is not exactly 3/4 in. 18 mm equals about 0.709 in, while 3/4 in equals 19.05 mm. For CNC work, router bits, grooves, shelves, and tight hardware clearances, measure your specific sheet.
Sources, Method and Limitations
All 18 row values for both finish groups come from the U.S. Department of Commerce’s PS 1-22 Table 10. No values were interpolated. Metric/inch pairs are displayed as printed in the standard; Appendix D’s nonmandatory recommended label is displayed separately from the actual permitted range.
- NIST / DOC — PS 1-22 Structural Plywood (October 2, 2023)Table 10, §5.10.2 and Appendix D.
- APA — Engineered Wood Construction GuideStructural sheathing category pairs 15/32 / 1/2, 19/32 / 5/8 and 23/32 / 3/4.
- ANSI/HPVA HP-1-2024Hardwood/decorative plywood uses separate requirements.
- Reference table
- 18 PS 1-22 categories · sanded and unsanded
- Units
- Source-published mm and inches; SI governs
- Reference condition
- Dimensions referenced to 9% moisture content
- Validated
- October 8, 2026
- Not covered
- OSB, MDF, Baltic birch, manufacturer-specific panels
Plywood Thickness FAQs
How thick is 3/4 plywood actually?
Check the panel’s marked category. Under PS 1-22, sanded 3/4 Performance Category permits 0.734–0.766 in (18.65–19.45 mm); sanded 23/32 Performance Category permits 0.703–0.734 in (17.86–18.65 mm). Both fractions may come up when people shop for roughly 3/4-inch sheathing. Other plywood products use other specifications.
What is the actual thickness of 1/2-inch plywood?
There is no one measurement for all products. PS 1-22 sanded 15/32 category plywood permits 0.453–0.484 in and sanded 1/2 category plywood permits 0.484–0.516 in. They are distinct categories; check the stamp.
Is 23/32 the same as 3/4?
No. 23/32 mathematically equals 0.71875 in; 3/4 equals 0.750 in. They are separate PS 1-22 categories with ranges that can meet or overlap.
Is 18 mm plywood the same as 3/4 plywood?
No. 18 mm is approximately 0.709 in; exactly 3/4 in is 19.05 mm. Sheet labeling and manufacturing standards vary; measure for precision work.
Can I determine the plywood category just by measuring thickness?
Not always. Published ranges can overlap, especially for unsanded panels. Use the printed Performance Category and governing standard, not caliper thickness alone.
What sizes do plywood sheets come in?
Common North American sheet footprints include 4 × 8 ft, with other panel sizes offered by product and supplier. Sheet length/width and panel thickness are separate dimensions; confirm both before cutting.
Related Engineering References
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