Plywood Grades Explained: CDX, AC, BC & A–D
Understand plywood grades before you buy: what A–D veneer grades mean, how AC and BC panels differ, why CDX is often misunderstood, and how Exposure 1 vs Exterior changes the decision.
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Plywood grades at a glance
| Marking | What it primarily tells you | Typical woodworking implication |
|---|---|---|
| A | Smooth, high-appearance veneer grade | Useful where a visible face needs a clean finish |
| B | Good appearance with more permitted repairs than A | Common choice for visible work where an A face is unnecessary |
| C | Utility veneer with more visible defects/repairs permitted | Often suitable for hidden faces or structural/utility work |
| D | Utility veneer with the greatest defect allowance of A–D | Appearance is secondary; D is not permitted for Exterior plywood under the APA guidance summarized below |
| Exposure 1 | Bond classification for limited exposure, including construction moisture | Not intended as a blanket substitute for Exterior in long-term weather exposure |
| Exterior | Bond classification intended for long-term weather/moisture exposure | Still does not mean decay-proof or maintenance-free |
APA describes veneer grades from A through D and separates appearance grade from bond classification and span/performance ratings.
What the two letters mean: AC, BC, CD and similar plywood
ACX and BCX are also common retail/trade shorthand. Treat the “X” as a cue to verify the panel’s actual exposure/bond marking rather than as a complete grade by itself; the full stamp and manufacturer specification govern the panel you are buying.
Letter-pair grades usually describe the veneer quality on the two outer faces. An A-C panel has a higher-appearance A face and a C back. B-C steps the visible face down one grade. The letters do not tell the entire story about structural capacity, thickness, bond classification, or core construction.
For woodworking, that distinction matters because the visible face may be the dominant concern on a cabinet side, while a structural panel in a building has a completely different set of requirements.
CDX plywood meaning: the common misunderstanding
CDX is often treated casually as if the “X” simply meant “exterior plywood.” That shortcut can lead to the wrong purchase. APA notes that plywood commonly called CDX is typically Exposure 1: it uses exterior-type adhesive but is not automatically intended for permanent, long-term exposure to weather.
If a project will remain exposed to weather or moisture long term, identify the actual Exterior bond classification and confirm the complete panel specification for the application rather than relying on the nickname CDX.
Exposure 1 vs Exterior plywood
Exposure 1
APA describes Exposure 1 panels as suitable where long-term weather exposure is not expected. They can tolerate moisture conditions such as construction delays, but the panel composition is not specified for permanent weather exposure.
Exterior
Exterior panels are intended for repeated wetting/drying or long-term weather/moisture exposure. Even then, bond classification is not a promise of fungal-decay resistance or maintenance-free service; design, detailing, protection, and treatment requirements still matter.
For structural work, follow the applicable building code and panel manufacturer guidance. This page is aimed at helping woodworkers read panel markings, not at replacing engineering or code requirements.
Plywood grades for cabinets and furniture
Cabinet and furniture work usually cares about a different set of qualities than roof or wall sheathing: face appearance, veneer consistency, flatness, core voids, thickness consistency, edge appearance, screw holding, and how well the panel machines and finishes.
A smooth A or B face can be useful when a surface will remain visible, but “cabinet grade” is not one universal structural grade designation. Compare the actual product construction and manufacturer specification, especially when exposed plywood edges, dados, veneer matching, or clear finishes are part of the design.
If you are deciding between solid wood and sheet goods for visible furniture, compare species in best wood for furniture and use the Janka hardness chart for solid-wood dent resistance.
Plywood thickness, Performance Category and span ratings
Modern structural-panel labels can include a Performance Category, decimal thickness designation, span rating, bond classification, and other marks. Do not assume a familiar nominal fraction is the only number that matters. For structural applications, use the complete grade stamp and the applicable design guidance.
Span ratings relate to structural use over supports; veneer face grades relate to appearance. Those are different dimensions of the product. A visually attractive panel is not automatically the right structural sheathing, and a rated sheathing panel is not automatically the best furniture surface.
How to choose plywood for a woodworking project
- Decide whether the panel is structural, furniture/cabinet, shop, or exterior-use material.
- Identify which faces will remain visible. Pay for higher face quality where it matters, not automatically on both sides.
- Confirm thickness/core construction for the joinery. Dados, edge banding, screws, and exposed edges all respond differently to panel construction.
- Check moisture/exposure classification. Do not infer Exterior performance from appearance grade or the word CDX alone.
- Calculate quantity. Use the plywood sheet calculator.
- Verify the actual part layout. Use the cut list optimizer for cabinets and furniture.
Authoritative plywood references
The grading and exposure distinctions above are grounded in APA’s plywood guidance and the current PS 1-22 Structural Plywood standard. APA specifically distinguishes veneer appearance grades, structural/performance ratings, and Exposure 1 versus Exterior bond classifications.
Frequently asked questions
What do A, B, C and D plywood grades mean?
A, B, C, and D describe veneer appearance and allowable repairs, with A providing the smoothest appearance grade and D allowing more visible defects. A panel designation such as A-B or B-C generally describes the face and back veneer grades; structural performance and exposure suitability require additional markings.
What does CDX plywood mean?
In common trade usage, CDX describes a plywood panel with C- and D-grade faces associated with an Exposure 1 bond classification. APA specifically cautions that panels commonly called CDX are Exposure 1, not automatically Exterior, so they are not the same thing as plywood intended for long-term weather exposure.
What is the difference between Exposure 1 and Exterior plywood?
APA states that Exterior panels are intended for applications subject to long-term weather or moisture exposure, while Exposure 1 panels are intended for uses that do not involve long-term weather exposure and can tolerate limited construction moisture. Bond classification does not by itself describe strength, stiffness, or decay resistance.
Is AC plywood better than BC plywood?
AC plywood has a higher-appearance A face and a C back, while BC has a B face and C back. AC can be the better choice when one visible face needs a smoother finish, but BC may be fully adequate when the appearance requirement is lower. The correct choice also depends on bond classification, thickness, structural rating, and project use.
What plywood is best for cabinets?
For visible cabinet parts, prioritize a smooth face, stable core, suitable thickness, and consistent panel quality rather than relying on one letter grade alone. Hardwood-faced cabinet plywood is often chosen for furniture and cabinetry, while structural sheathing grades are intended for different jobs. Match the panel to the finish and joinery you plan to use.
Do plywood grades tell me how many sheets to buy?
No. Grade describes the panel; quantity is a separate calculation. Use the plywood calculator for a quick sheet estimate and the cut list optimizer when individual part dimensions determine the layout.