Answers
Most KDP paperback rejections come from file setup, not content: text or page numbers outside the margins, a gutter too small for the page count, pages that don’t match the trim size, fonts that aren’t embedded, or a cover whose spine doesn’t match the page count. Find your error below; most can be fixed in minutes without re-typesetting.
Why it happens: Text, page numbers, headers or images sit closer to the edge than KDP allows: 0.25 in on the top, bottom and outside, and a gutter of 0.375–0.875 in by page count. Page numbers placed very low are the most common cause.
How to fix it: Widen the margins in your source file and re-export, or let us rescale every page uniformly into the live area (pagination unchanged; by default the text ends up at least 0.08 in inside the lines).
Why it happens: The inside margin is narrower than KDP requires for your page count — often because the book grew past 150, 300 or 500 pages after the document was set up, or margins aren’t mirrored.
How to fix it: Use the gutter for your final page count (0.5 in for 151–300 pages) with mirrored margins. Our fix centres odd and even pages in their own live areas, so the gutter lands on the spine side.
Why it happens: The PDF was exported at A4, US Letter or another size than the trim you selected in KDP, or a few pages (inserts, images) have a different size.
How to fix it: Export at the exact trim size, or let us rebuild every page at the trim size with the content scaled uniformly. Below about 85% scale the text gets noticeably smaller, and we tell you so.
Why it happens: Printed books always have an even number of pages. KDP pads an odd count with a blank page, which changes the page count your cover’s spine was built for.
How to fix it: Add one blank page at the end before you upload, and build the cover for the even count. Our fix does both.
Why it happens: The cover was made for a different page count or paper (cream paper is thicker than white), so the spine is too wide or too narrow and the cover is the wrong overall width.
How to fix it: Recalculate: spine = pages × paper thickness (0.002252 in per page on white), cover = 2 × trim width + spine + 0.25 in bleed.
Why it happens: KDP allows spine text from 79 pages and wants it at least 0.0625 in from each fold, so it doesn’t wrap onto the front or back.
How to fix it: Remove spine text on books under 80 pages; otherwise shrink it to fit inside the spine with 0.0625 in on each side. Our cover builder does this automatically.
Why it happens: Text or important art sits where KDP prints the ISBN barcode, at the bottom right of the back cover.
How to fix it: Keep a 2 × 1.2 in box clear in the bottom-right corner of the back cover, 0.25 in from the trim. Our templates and covers mark and keep it empty.
Why it happens: The PDF refers to a font without including it, so KDP can’t print the text reliably.
How to fix it: Re-export with all fonts embedded (Word: Save as PDF → Options → “PDF/A compliant”; Canva: “PDF Print”). We detect it and name the fonts, but can’t add a font that isn’t in the file.
Why it happens: Images below 300 DPI at their printed size look blurry, and KDP flags them.
How to fix it: Replace them with higher-resolution images and re-export. We don’t check image resolution yet.
Why it happens: You chose “bleed” in KDP but the PDF has no bleed (or the reverse). Bleed pages are 0.125 in wider and 0.25 in taller than the trim.
How to fix it: Match the KDP setting to your file. Bleed interiors (picture books) aren’t supported by our fix yet — coming soon.
KDP’s exact wording changes from time to time; the names above are the problems its reviewers and Print Previewer flag.
Source: KDP Help: Set Trim Size, Bleed, and Margins · KDP Help: Create a Paperback Cover. Checked .
Almost always a file-setup problem: content outside the margins, a gutter too small for the page count, pages that don’t match the trim size, non-embedded fonts or a cover with the wrong spine width. Each one has a cause and a fix on this page.
Widen the margins in your source file and re-export, or let us rescale every page uniformly into the live area (pagination unchanged; by default the text ends up at least 0.08 in inside the lines).
Yes. Our free check renders every page of your PDF and measures it against KDP’s margins for your page count and trim size, and lists the exact pages that would be flagged.
Email us and you get a full refund of the $9. KDP’s previewer is the final authority, so always check the fixed file there before publishing.
No. We don’t reflow text: every page keeps its content and order, scaled uniformly and moved inside the margins. Only an odd page count gets one blank page at the end.