How to Format a Paperback for KDP (Margins, Gutter, and Bleed)
KDP rejects paperbacks for a short list of predictable reasons: margins too tight for the page count, no gutter allowance, wrong trim, or bleed set incorrectly on images. Set a mirrored inside margin that grows with page count, keep body text off the edges, and only use bleed if art runs to the trim. Get these four right and preflight passes.
Almost every KDP paperback rejection comes down to four settings. Get these right and your upload passes the first time. Get one wrong and you get the rejection email, fix it, re-upload, and wait again. Here’s each, in plain terms.
Trim size
Pick a supported trim before anything else, because it changes every other number on this page. If you haven’t chosen yet, read choosing a trim size first. Don’t format and then switch trim, you’ll redo all of it.
Margins and the gutter
The gutter is the extra inside margin that disappears into the spine. The key thing people miss: it has to grow with page count. A 200-page book needs less inside margin than a 600-page one, because a thick book curves more at the spine and swallows more of the page.
KDP publishes a page-count-to-margin table, and it’s worth following exactly. Set too little inside margin on a long book and your text literally curves into the binding where nobody can read it. Keep outside margins generous too, so body text isn’t kissing the trimmed edge.
Bleed
Bleed only matters if an image, ornament, or background colour runs all the way to the edge of the page. If it does, you extend the art past the trim by KDP’s 0.125” bleed allowance so there’s no white sliver after trimming.
For a normal text novel, you don’t need bleed at all, and turning it on when you don’t need it just confuses your margins. Most fiction interiors are text on white, so leave bleed off unless you’re deliberately printing to the edge.
Page count and spine
KDP has minimum and maximum page counts per trim, and paperbacks generally need an even page count, which is why a blank page sometimes gets added at the end. Your spine width, needed for the cover, comes straight from the final page count, so finalise the interior before you build the cover.
Preflight before you upload
The whole game is catching these on your desk instead of in Amazon’s rejection email. Galley includes a KDP preflight that checks trim, margins, metadata, and page count against KDP’s rules before you export, so the four things above are already correct when you hit upload. It comes out of the same book as your EPUB, so the two never drift apart.
Two free tools cover the numbers this post keeps leaning on. The spine width calculator turns a final page count into a cover, and the KDP royalty calculator turns it into a print cost and the lowest price Amazon will let you charge.
More on publishing
- Standard Manuscript Format, and What Agents Actually CheckThe Shunn manuscript format specification in plain terms: font, spacing, margins, indents, scene breaks, the running header, and the word count that should be rounded.
- Writing Software for Novelists Who Don't Write in EnglishHow to write and typeset a book in Arabic, Persian, Urdu, Hebrew, Hindi, Bengali, Thai, Japanese, Chinese, Korean, Russian, Greek or Vietnamese, which typeface each script gets, and what still needs building.
- Accessible Ebooks and the European Accessibility ActWhat the EAA means for a self-published novel sold in the EU: accessibility metadata, what makes an EPUB accessible, the microenterprise exemption, and the large-print edition nobody makes.