There are four grades of plyveneer: A, B, C, and D. A-grade plywood is the highest quality. While it will cost more, the time savings can be worth it for projects that will be visible to the eye. This type of plywood is smooth and easy to paint.
A has the highest quality and is the most expensive, and D is the least expensive. A-grade plywood features a smooth, sanded surface without knots. Any wood defects have been repaired with synthetic filler, so the veneer can be painted. A-grade ply is ideal for furniture or cabinet doors.
B-grade ply usually has minor flaws that may require small repairs. It is slightly less smooth.
C-grade plywood has more visible flaws and knots up to 1.5 inches in diameter.
D-grade plywood can have large flaws and knots up to 2.5 inches in diameter. This is typically the cheapest of veneer.
The first letter refers to the grade of the face of the plywood, and the second letter refers to the back. Therefore, “AB” plywood would have an A-grade face veneer and a B-grade back sheet.