Gutter is the term for the bound sections (inner margins) of a book, magazine or other publication. It also refers to the margins between the printed text and the binding on any book or magazine surface.

Setting the correct margin for the gutter when compiling a book is important for ensuring easy readability. Due attention must be given to the book’s specifications, type of paper used and its binding method. With saddle bound booklets such as weekly magazines and manga publications where double folds are bound with wire staples, it is important to remember that the inner and outer gutter dimensions will differ as the thickness of the booklet increases. In other words, this produces differences in the landscape dimensions. In addition, when placing a single photograph or string of text spread over the left and right pages for display when the book is open, if the presence of the gutter is not taken into consideration, the key images in the center of the photograph will be hidden by the binding or the central part of the text will be impossible to read. When planning a booklet it is important to consider beforehand how much of the gutter will be hidden.