Plywood Grade Converter
Look up plywood grade letters, descriptions, and standard thicknesses.
Compare grades A through D and their recommended uses.
Select a plywood grade or thickness to see details and recommended uses.
Plywood is graded by the quality of its face and back veneers, using letters A through D. The grade is written as two letters: the first is the face quality, the second is the back quality (e.g., A-C means A-grade face, C-grade back).
Plywood veneer grades:
| Grade | Quality | Description |
|---|---|---|
| A | Premium | Smooth, sanded, paintable. Minimal repairs visible. Suitable for visible surfaces. |
| B | Good | Solid surface with minor repairs, small knots, and patches allowed. Can be painted. |
| C | Utility | Knotholes up to 1.5 inches, some splits. Good for structural use where appearance does not matter. |
| C-Plugged | Improved utility | Better than C, knotholes filled with patches. Used as underlayment. |
| D | Economy | Large knotholes, splits, and defects allowed. For interior structural use only. |
Common plywood grade combinations and uses:
| Grade | Typical Use |
|---|---|
| A-A | Cabinet doors, furniture, visible both sides |
| A-B | Cabinet sides, shelving (one good side visible) |
| A-C | Siding, exterior projects (one finished side) |
| B-C | Utility shelving, backing, subflooring |
| C-C (CDX) | Roof sheathing, subflooring, exterior structural |
| C-D | Wall sheathing, temporary construction |
Standard plywood thicknesses:
| Nominal (inches) | Actual (inches) | Metric (mm) |
|---|---|---|
| 1/4" | 0.215" | 5.5 |
| 3/8" | 0.340" | 8.5 |
| 1/2" | 0.451" | 11.5 |
| 5/8" | 0.578" | 14.5 |
| 3/4" | 0.703" | 18.0 |
| 1" | 0.953" | 24.0 |
| 1-1/8" | 1.078" | 27.5 |
Note: Actual plywood thickness is always slightly less than the nominal (labeled) thickness due to sanding and manufacturing tolerances.
Exposure ratings (separate from veneer grade):
- Exterior: Waterproof glue, suitable for permanent outdoor exposure.
- Exposure 1: Moisture-resistant glue, handles temporary exposure during construction but not permanent outdoor use.
- Interior: Not moisture-resistant, for indoor use only.
CDX explained: CDX is the most commonly sold plywood. “CD” means C-grade face, D-grade back. The “X” stands for Exposure 1 rating (not Exterior), meaning it can handle temporary moisture during construction.
Practical tip: For painted furniture and cabinets, B-grade plywood with wood filler and sanding produces a finish nearly as good as A-grade at a significantly lower cost.