How deep should a bookcase be to hold books properly?

Don't just chase depth for a bookcase. Regular books are about 25 cm tall, so a cabinet depth of 28 to 30 cm is enough for the vast majority of books. Making it too deep is a waste instead: books in the back row are hard to reach and tend to collect dust. If you store art albums or document boxes, you can go to 32 to 35 cm. Also, don't make the shelf span too large; if it exceeds 80 cm, it is recommended to thicken the board or add vertical panels, otherwise it will sag easily. For the board material you can choose particle board, plywood, eco board, or OSB; for environmental grades, HENF, ENF, E0, FAS, and F4 star are available; for edge banding, PUR edge banding or laser edge banding can be used.