Bleed (printing)

Bleed is ink that runs past the edge where the page will be cut: KDP defines it as "when printed objects on a page, such as images, background color, or graphics, extend past where the publication will be trimmed." Because cutting is never perfectly placed, an image meant to reach the edge must run past the trim, or a thin white sliver shows where the blade missed. KDP trims 0.125 in (3.2 mm) from the top, bottom and outside edges, so full-bleed elements must extend that far past the trim. If even one page bleeds, the entire file must be set up with bleed, and covers always require it.

For the author the rule is: bleed only when ink reaches the edge. Plain prose interiors need none, and skipping it keeps the outside-margin minimum at 0.25 in instead of 0.375 in. The PDF page itself is trim size plus bleed (6 x 9 becomes 6.125 x 9.25); the setup walkthrough is how to create a print-ready PDF.