What Makes a Book “Print-Ready”? The Complete Pre-Publish Checklist
A book is “print-ready” when its interior PDF and cover meet KDP's exact specs: the correct trim size, 0.125″ bleed if any content runs to the edge, outside margins of at least 0.25″ and a gutter that scales with page count, all images at 300 DPI, all fonts embedded, single pages (not spreads), and a full-wrap cover with the spine width calculated from the page count. Miss any one and the file is rejected.
“Print-ready” isn't a vibe — it's a checklist. KDP's automated review checks your files against specific numbers, and the most common rejections come from margins, bleed, resolution and spine math. Here's every requirement, in order, so your file passes the first time.
What are the KDP interior file requirements?
- Trim size: your document must be built to the exact trim (e.g. 6″×9″). It cannot be changed after publishing.
- File format: PDF is safest. Submit single pages, not spreads. Flatten transparency and layers.
- Fonts: every font must be embedded in the file.
- Images: minimum 300 DPI throughout.
- No crop marks, registration marks, comments, bookmarks or placeholder text. Max file size 650 MB.
What bleed and margins does KDP require?
Bleed is required (0.125″ / 3.2 mm on all outer sides) only if any content — an image or color block — runs to the edge of the page. Even one bleed page means the whole file must be set up with bleed. For a 6″×9″ trim, the bleed page size becomes 6.125″ × 9.25″.
Margins are where most files fail. The outside/top/bottom margin must be at least 0.25″ (0.375″ if the book uses bleed). The inside gutter margin grows with page count so text doesn't disappear into the spine:
| Page count | Minimum gutter |
|---|---|
| 24–150 | 0.375″ |
| 151–300 | 0.5″ |
| 301–500 | 0.625″ |
| 501–700 | 0.75″ |
| 701–828 | 0.875″ |
This dynamic gutter is the single most common cause of rejection: a fixed inside margin that was fine at 150 pages will fail once the book crosses 300. Maximum length is 828 pages.
How do you calculate the spine width for the cover?
The cover is a single full-wrap file: back cover + spine + front cover. Spine width depends on page count and paper type:
- White paper: page count × 0.002252″
- Cream paper: page count × 0.0025″
- Standard color: page count × 0.0032″
Example: a 300-page cream-paper book has a spine of 300 × 0.0025 = 0.75″. KDP only prints spine text on books over 79 pages — thinner books get a blank spine. Always generate the cover template for your final page count, because if you edit the interior and the page count changes, the spine width changes too and the cover must be rebuilt.
What front and back matter should a print book include?
- Front matter: title page, copyright page, dedication (optional), and table of contents.
- Body matter: your chapters, with consistent running heads and page numbers.
- Back matter: about-the-author, also-by page, and a call to action (e.g. “please leave a review”).
- Keep essential text and logos at least 0.25″ inside the trim line so nothing is cut during trimming.
Common print-ready mistakes that cause rejections
Beyond the core specs, these recurring errors send files back at review — each is easy to prevent once you know it:
- Fixed gutter on a growing book. A 0.375″ inside margin is fine at 150 pages but fails past 300. Set the gutter to your final page count.
- Low-DPI images that look fine on screen. A 72-DPI web image displays perfectly on a monitor but prints blurry and can be flagged. Use 300-DPI source files sized at their print dimensions.
- Fonts not embedded. If the font isn't embedded, KDP substitutes or rejects it, breaking your layout. Export to PDF/X or tick “embed all fonts.”
- Spine text on a too-thin book. Adding spine text under 80 pages gets the cover rejected — leave the spine blank or add pages.
- Spreads instead of single pages. Export one page at a time, never two-page spreads.
- Leftover marks or comments. Crop marks, editorial comments and bookmarks must be removed before upload.
Almost every rejection traces back to one of these — not to your writing. A careful pass against this list before uploading usually clears review on the first try.
The print-ready checklist at a glance
- Document set to the exact trim size.
- Bleed 0.125″ on outer edges (only if content bleeds).
- Outside margin ≥ 0.25″; gutter correct for page count.
- All images ≥ 300 DPI; all fonts embedded.
- Single-page PDF, no marks, comments or spreads.
- Cover spine width calculated from final page count; spine text only if 79+ pages.
- Previewed every page in KDP's online previewer before publishing.