The spine width depends on the number of pages, the material and the thickness of your hardcover books. Check out our guide for an overview so you can print your own book without a hassle, [Spine Width Table - Hardcover Booklets](//assets.ctfassets.net/wm1n7oady8a5/7hdeNFsOG3yvt18q1snjN3/e8e150a0cef62f46493c940936bd3523/Spine_Width_Table_-_Hardcover_Booklets__4_.pdf)