Free checker
Check Your PDF for KDP Before You Upload It
Drop in the interior PDF and get KDP's own checks in seconds: trim size, page count, the inside margin your page count needs, the 0.25″ no-print zone, embedded fonts and picture resolution — with what to fix.
KDP rejects more interiors for geometry than for anything else: a page size that is not the trim, an inside margin too small for the page count, a running head inside the 0.25″ safety zone, a font that was not embedded. The previewer tells you something is wrong; it rarely tells you where. This checker reads your PDF the way the previewer does — every page's size, where the text actually sits on each page, which fonts ship inside the file, how sharp each picture prints — and reports each rule with the page numbers and the fix. It runs in memory and keeps nothing.
Free, no account Seconds per file Nothing stored
Last updated: October 16, 2026 · Reviewed by the Ceeryo team
Free, no account. The file is read, reported on and forgotten.
Real output
What the typeset pages actually look like
Chapter opener and body page from each interior theme — rendered from the engine's real output at 6×9, not mockups.
How it works
From manuscript to book in four steps
The fastest way from a finished Word manuscript to print-ready files — no templates, no desktop app, no per-page fiddling.
- Step 1
Upload your manuscript
Drop in the .docx manuscript you have finished writing. Your file is processed only to typeset it and is never used to train models.
- Step 2
Chapters are detected
Chapter openings, scene breaks and italics are found automatically, without changing a word of your text.
- Step 3
The book is typeset
Trim size, margins and gutter, running heads, drop caps and chapter openers are set as a real book interior.
- Step 4
Download print PDF + EPUB
A print-ready interior PDF at your chosen trim size plus a clean EPUB, checked against the geometry KDP enforces.
In short
To pass KDP's file review a paperback interior needs every page at the trim size (or trim plus 0.125″ bleed), 24–828 pages, an inside margin that meets the gutter for its page count (0.375″ to 150 pages, up to 0.875″ at 828), nothing within 0.25″ of the outside edges, and every font embedded. This free checker measures all of that on your PDF and names the pages that fail.
Why does KDP say my margins are wrong?
Because the inside margin must grow with the page count — 0.375″ up to 150 pages, 0.5″ to 300, 0.625″ to 500, 0.75″ to 700, 0.875″ to 828 — and the outside, top and bottom must keep 0.25″ clear (0.375″ with bleed). Page numbers and running heads are the usual offenders. The checker measures where your text sits on every page and tells you the smallest margin it found, and on which page.
Measured, not guessed
It reads where your text actually is
A margin setting in Word is not a margin in the PDF: headers, footers, text boxes and pictures all sit outside it. The checker measures the ink on every page — text blocks, drawings and pictures — against the trim edges, with page 1 as a right-hand page, exactly as KDP's previewer judges it.
- Trim detected from the page size, including bleed-sized pages
- Inside margin measured per page against the gutter for your page count
- Fonts listed by name when one is not embedded
- Pictures under 300 dpi named with their page
Features
Why authors choose Ceeryo
Every KDP geometry rule
Trim size, consistent page sizes, page-count range, gutter by page count, 0.25″ safety zone, embedded fonts — each with a sentence and a fix.
Page numbers for every problem
The report names the first pages that fail each rule, so you can open the file and look.
Nothing stored
The PDF is read in memory, reported on and forgotten. No account, no email.
Use cases
Where Ceeryo works best
KDP rejected the file
Find out which rule failed and on which page, instead of guessing from the previewer's warning.
Before the first upload
Export from Word, InDesign, Vellum or Atticus and check the geometry before KDP's 24-hour review.
A formatter's deliverable
Paid someone to format the book? Check what they sent before you accept it.
Why not do it by hand?
Ceeryo vs. doing it manually
Typesetting a book by hand in Word or InDesign takes days and rarely passes KDP's checks the first time. Here's the difference.
Output quality
What the finished book files look like
Every run produces a preflight-checked print PDF and a clean EPUB — never a rewrite of your words. Here's what you get.
- The trim KDP will see, and whether the pages carry bleed
- The smallest inside, outside, top and bottom margins found, with page numbers
- Fonts referenced but not embedded, by name
- Pictures that will print soft, with their resolution and page
Topic cluster
Related book formatting tools
Other ways to turn your Word manuscript into a finished book.
A Press-Ready Book PDF for Any Printer
Typeset your manuscript, then download the interior a commercial printer asks for — CMYK, PDF/X, crop marks and 3 mm bleed — beside the PDF for KDP and the EPUB.
printformatterKDP margin checker
Every margin calculator repeats Amazon's table. The question that gets books rejected is whether your PDF actually meets it.
printformatterFormat Your Book for Amazon KDP in Minutes
Upload your .docx manuscript, pick a trim size and interior theme, and download a print-ready PDF that passes KDP's checks — plus an EPUB for the Kindle edition.
printformatterTurn Your Manuscript into a Print-Ready PDF
From double-spaced draft to typeset book interior — trim size, margins, chapter design, and preflight in one pass.
printformatterFormat Your Paperback Interior
The inside of the book, done to trade standards — so your paperback reads like it came from a publisher.
printformatterKDP trim sizes, and how to choose one
The trim you pick changes your page count, your printing cost per copy, and how the book reads in the hand.
printformatter
Frequently asked questions
Does the checker fix the PDF?+
No — it tells you exactly what is wrong and where. To fix it, change the margins or fonts in the program that made the PDF and export again, or upload the Word manuscript to Ceeryo and let it set the book with the right trim, gutter and fonts.
Which trim sizes does it recognise?+
All of KDP's paperback trims — 5 × 8, 5.06 × 7.81, 5.25 × 8, 5.5 × 8.5, 6 × 9, 6.14 × 9.21, 6.69 × 9.61, 7 × 10, 7.44 × 9.69, 7.5 × 9.25, 8 × 10, 8.25 × 6, 8.25 × 8.25, 8.5 × 8.5, 8.5 × 11, A4 and A5 — with or without 0.125″ bleed.
Is a picture under 300 dpi a rejection?+
No. KDP accepts the file and prints the picture a little soft; the checker reports it as a note, not a failure, so you can decide whether to replace the picture.
How big a file can I check?+
Up to 60 MB, read straight from your browser. The file is never stored.
Would you rather not fight the margins at all?
Upload the Word manuscript and Ceeryo sets the whole book — right trim, right gutter for the page count, fonts embedded — and runs these checks before you download.