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Why Your Book Got Rejected
The EPUB & KDP Formatting Guide for 2026
Free download available after Dec 5, 2026Format, validate, clean and prepare your ebook before publishing.
The EPUB & KDP Formatting Guide for 2026
Free download available after Dec 5, 2026All tools
What the scan gives back
Preview — not connected to live data
Upload your .docx or .txt file. We detect chapters, clean formatting errors, and generate a valid EPUB 3.0 file in one step. No Calibre. No Sigil. No coding.
Our own experience
While formatting Why Your Book Got Rejected, we found a real bug: the EPUB Formatter was leaving raw --- section breaks as literal text in the generated EPUB — so instead of a clean scene break, readers saw the dashes merged into the surrounding paragraph.
Before
...end of a paragraph. — — Next paragraph starts here...
Raw dashes merged into surrounding text
After
...end of a paragraph.
* * *
Next paragraph starts here...
Clean scene break, correct EPUB output
We found it, fixed it, and shipped the fix — before it ever shipped in your book. See the book we built it on →
Simple, honest pricing
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See pricingEPUB & KDP questions
EPUB is the standard file format for eBooks. It stands for Electronic Publication. When you upload an EPUB to KDP, Amazon converts it to the Kindle format for you. A clean, valid EPUB means your book looks right on every Kindle device. Upload a broken file and KDP may reject it or show your readers garbled text.
Apple Books has stricter EPUB rules than Amazon. Amazon often accepts files with minor errors; Apple Books rejects them outright. Common reasons for rejection include a cover image that is too small, a missing or broken table of contents, or metadata that does not match the file. Run your EPUB through a validator before uploading. Fix every error flagged and re-upload.
Most KDP formatting errors start in Word. The usual problems are smart quotes that turn into question marks, tab indents that Kindle ignores, and extra blank lines between paragraphs. Fix them before you convert to EPUB — not after. Our Kindle Format Fixer corrects eight common errors in your browser. Clean the file first, then convert.
EPUB 2 is the older format. It works on most eReaders but lacks support for better fonts and accessibility features. EPUB 3 is the current standard. KDP, Apple Books, and Kobo all prefer EPUB 3 now. If you are formatting a new book, use EPUB 3. It gives you a clickable table of contents, better font control, and wider platform support.
No. Amazon assigns a free ASIN (Amazon Standard Identification Number) when you publish on KDP. You only need an ISBN if you plan to sell on other platforms like IngramSpark or Kobo. ISBNs are free in some countries and cost money in others. If you are only publishing on Amazon, you can skip the ISBN entirely. Add one later if you expand to other stores.
A Kindle table of contents needs to link to actual chapters in your EPUB file. The easiest method is to use heading styles (H1 for chapters, H2 for sections) in Word before you convert. Our TOC Generator takes your chapter headings and outputs the correct HTML for Kindle. Paste it into your EPUB and readers can tap any chapter to jump straight there.
KDP requires a cover that is at least 2,560 × 1,600 pixels. The ideal ratio is 1.6:1 (height to width). The file must be a JPEG or TIFF, under 50 MB. A cover smaller than these requirements gets rejected before your book goes live. Apple Books requires a minimum of 2,400 × 1,600 pixels. Our Cover Checker verifies your image against all platform requirements before you upload.
The key is to use proper styles in Word before you convert. Use Heading 1 for chapter titles, Heading 2 for subheadings, and Normal for body text. Avoid using tabs or spaces to indent paragraphs — use paragraph indent settings instead. Our Full Manuscript Mode converts your DOCX or TXT to EPUB 3.0 in one step. It detects chapters automatically and fixes the most common Word formatting problems.
EpubCheck is the official EPUB validation tool. It checks your file against the EPUB standard and lists every error. KDP and Apple Books both run EpubCheck automatically when you upload. If your file fails, it gets rejected. Our EPUB Validator runs the same checks in your browser with no Java install. Fix errors before you upload and avoid the back-and-forth rejection cycle.
Free tools like Calibre and Sigil work well but require setup and a learning curve. Paid tools like BookKraft AI run in your browser with no install. They target specific formatting problems — smart quotes, spine errors, missing metadata — and surface them faster than a manual check. If you publish one book a year, free tools are fine. If you publish regularly, a dedicated tool saves hours per book.
Common questions