First of all, we need to know the size of your bookcase, whether it is single-sided or double-sided. Generally, the size of a double-sided bookshelf is about 1000 * 600 * 2350 mm. Each side of a double-sided bookshelf can be divided into six layers, and the height of each layer is about 355 mm-370 mm. If it is a single-sided bookshelf, it can hold 36 layers. Suppose the size of each book is: 30w * 2350 mm.