How to Upload EPUB to Amazon KDP

Amazon KDP has accepted EPUB directly since 2021 — you don't need to convert to MOBI or AZW3, and you shouldn't upload DOCX or PDF either (KDP will silently convert them and the result is rarely what you intended). The format decision is easy. The hard part is getting the EPUB through KDP's validation without rejection cycles.

What KDP actually wants

KDP's upload accepts EPUB 2 and EPUB 3 (EPUB 3 recommended). The real constraints most guides skip:

• File size: 650 MB is the upper limit, but you care about the compressed size because Amazon charges $0.15/MB in delivery fees against the 70% royalty tier. A 5 MB file costs you $0.75 per sale; a 50 MB file costs $7.50. Run the compressor before uploading.
• No embedded DRM: KDP applies its own DRM (or none, if you opt out). Your upload must be unencrypted.
• ISBN is optional: KDP assigns a free ASIN. Use your own ISBN only if you want to appear in non-Amazon catalogs or you already have one.
• Cover is uploaded separately, but it's still a good idea to embed one in the EPUB for preview consistency — see below.

Pre-upload checklist

1. Validate the file. Run the EPUB validator with deep scan. Fix all errors — KDP rejects files that fail EPUBCheck. Warnings are usually tolerated.
2. Set metadata correctly. Open the metadata editor. Title, author, language, and description must all be populated. Language code must be a valid BCP-47 string (en-US, not en US). KDP uses some of these fields to pre-fill the upload form.
3. Embed a working cover. 1600 × 2560 px, JPEG, RGB, under 2 MB. KDP asks for a separate cover upload but an EPUB with a broken internal cover looks wrong in the Kindle preview.
4. Compress. Run the compressor. Target: under 10 MB for text-heavy books, under 25 MB for image-heavy. Your royalty check will thank you.
5. Verify the table of contents. Kindle requires a navigable TOC. If your EPUB was generated from a Word doc with heading styles, the TOC is automatic. If not, add one in Sigil or Calibre.
6. Preview on a real Kindle. Use Amazon's free Kindle Previewer desktop app before uploading. It reflows the book like a real Kindle and catches layout issues Amazon's online preview doesn't.

The 6 most common KDP rejection reasons

"Book contains typos, spelling errors, or formatting issues"

Often a false positive. Usually triggered by merged paragraphs from bad OCR, lines like This is the end.[page 42] left over from print, or a high density of obvious misspellings. Spell-check the source before converting — don't try to fix these in the EPUB.

"The eBook's quality is unacceptable"

The vague one. Usually one of: images below ~96 DPI, blank pages, a scrambled table of contents, or text that doesn't reflow (a scanned PDF converted to EPUB without OCR). Fix the root cause in the source — don't re-upload hoping for a different reviewer.

"The book contains copyrighted content"

Triggered by quoted lyrics, long excerpts from other books, or public-domain content you didn't attribute. Also triggered if your book matches something already published in Amazon's plagiarism scanner. The fix: remove the flagged content or appeal with written permission.

"Book format is not supported"

Usually means EPUBCheck would reject the file. Run the validator and fix every error before re-uploading. See how to fix EPUB errors.

"Missing publication rights"

KDP thinks you don't own the rights. Common triggers: uploading a translation without attribution, uploading a public-domain work without marking it as such, or uploading with an author name that doesn't match your account name. Set author metadata correctly and, if it's public domain, select that status at upload time.

Metadata mismatch

Title or author in the EPUB doesn't match the title or author in the upload form. KDP compares the two and will reject on large differences. Use the metadata editor to align them before uploading.

The upload flow

Once the file is clean: log into kdp.amazon.com → Create a new title → Kindle eBook → fill in title, author, description, categories, keywords, age range → upload EPUB → upload cover → set pricing and royalty (70% for $2.99-9.99, 35% otherwise) → submit. First review takes 24-72 hours. Amendments take the same, so every failed review is a 2-3 day delay.

After the book is live

KDP regenerates the Kindle-format file on upload. If you later make changes, re-upload a new EPUB and KDP will re-review it. Readers who already purchased don't auto-update unless you flag the change as a critical fix during the re-upload — most amendments do not qualify. Save the exact file you uploaded; if KDP ever asks you to re-submit, you want to start from what worked.

Related

• Validate EPUB — run this before every upload
• Edit EPUB metadata — align title, author, language
• Compress EPUB — reduce file size and delivery fees
• Full self-publishing guide
• How to fix EPUB errors