Getting a "file failed our review" email from KDP after you've already announced a launch date is miserable. Almost every rejection traces back to one of a handful of measurable numbers: trim size, bleed, margins, spine width, DPI. Here's the checklist, in full.
1. Page size: trim and bleed
Your PDF page size has to be exact. Anything with art running to the edge needs bleed — KDP adds 0.125" to the outside edges for that.
Trim size → PDF page size with bleed:
- US comic single issue — 6.625" × 10.25" → 6.75" × 10.5"
- Manga / digest — 5" × 7.5" → 5.125" × 7.75"
- Trade paperback — 6" × 9" → 6.125" × 9.25"
- Workbook / art book — 8.5" × 11" → 8.625" × 11.25"
bleed page width = trim width + 0.125 · bleed page height = trim height + 0.25
Keep anything that must not be cut (lettering, panel borders you care about) at least 0.375" inside the trim edge.
2. Interior margins and gutter (KDP paperback)
Page count → inside gutter / outside margin (no bleed) / outside margin (with bleed):
- 24–150 pages — gutter 0.375", outside ≥ 0.25" (no bleed) / ≥ 0.375" (with bleed)
- 151–300 pages — gutter 0.5", outside ≥ 0.25" / ≥ 0.375"
- 301–500 pages — gutter 0.625", outside ≥ 0.25" / ≥ 0.375"
- 501–700 pages — gutter 0.75", outside ≥ 0.25" / ≥ 0.375"
- 701–828 pages — gutter 0.875", outside ≥ 0.25" / ≥ 0.375"
3. Spine width (paperback cover math)
- Black & white, white paper:
pages × 0.002252"
- Black & white, cream paper:
pages × 0.0025"
- Standard color:
pages × 0.002252"
- Premium color:
pages × 0.002347"
full cover width = back trim + spine + front trim + 0.25" bleed · cover height = trim height + 0.25"
Spine text needs roughly 100+ pages of thickness to read at all — keep it 0.0625" away from the spine edges either way.
4. Color, resolution, files
- All raster art at 300 DPI at final print size — never upscale to get there.
- KDP accepts RGB PDFs and converts to CMYK; expect slight darkening of saturated colors.
- Body text and lettering in pure black, not rich black or dark-gray builds.
- All fonts embedded in the PDF.
- Transparency flattened; no layers, comments, or form fields.
- One single PDF for the interior; the cover is its own single-page PDF.
- Page count is even and matches what you enter in KDP.
- No trim marks, registration marks, or color bars in the file.
5. The ten classic rejection causes
- Wrong PDF page size for the trim you selected
- Art meant to bleed that stops at the trim line
- Live text or panels drifting into the gutter
- Fonts not embedded
- Images below 300 DPI (soft, pixelated print)
- Cover spine width wrong for the page count
- Barcode zone on the back cover not kept clear (2" × 1.2")
- Interior page 1 starting on the wrong side (odd pages are right-hand)
- ISBN/imprint page mismatch with KDP metadata
- Copyrighted content you cannot prove rights to
6. Digital siblings (webtoon & CBZ)
- Webtoon strip: 800 px wide, episodes sliced into pieces no taller than 1280 px, JPG/PNG under 20 MB per episode.
- CBZ: page images numbered in reading order, RGB, 2000 px+ on the long edge reads well on tablets.
Standards above are the long-stable published ones — before a big print run, always verify current values on KDP's own print specifications page.
Get the templates: the Print-Ready Pack has the trim/bleed page templates above (comic, book, webtoon) as ready-to-use files, plus this checklist as a PDF.
Disclosure: this post and the pack it links to are put together by Sloom Studio, the app used to make the templates.