Plywood grades confuse everyone. The letter system isn’t intuitive. Here’s the breakdown.
The Letters
A is the best face – smooth, minimal defects, paintable or stainable.
B allows some repairs – patches, plugs. Still decent looking.
C has knots and voids. Structural but not pretty.
D is rough. Knotholes, splits. Use where nobody sees it.
Two Letters Mean Two Faces
A-C means one good face (A) and one rough face (C). For cabinets where only the front shows.
B-B is decent both sides. Utility shelving.
C-D or CDX is construction grade. Subfloors, sheathing. The X means exterior glue.
Core Types
Veneer core – layers of thin wood. Strong, relatively light. Standard for most work.
MDF core – smooth and flat but heavy. Great for painted work. Screws don’t hold as well.
Particle board core – cheapest and heaviest. Economy applications only.
What To Buy
Cabinet projects: A-C or B-C with veneer core. Good face out, ugly face against the wall.
Paint-grade: MDF core or Baltic birch. Smooth surfaces hide nothing so you need flat.
Shop jigs: Whatever’s cheap. CDX works fine. Nobody’s judging your router templates.
Baltic birch is special – void-free throughout, all birch layers. Expensive but beautiful edges. Worth it for drawer boxes and visible plywood edges.
