📋 In This Guide
Kindle eBook File Formats — Which to Use in 2026
This Kindle eBook formatting guide starts with the most important decision: which file format to upload. Amazon KDP accepts EPUB, HTML, DOCX, and RTF. Since Amazon deprecated MOBI uploads in 2022, that option is no longer available. Here is how each format compares for a Kindle eBook.
| Format | Quality | Control | Best For | Recommended? |
|---|---|---|---|---|
| EPUB | ⭐⭐⭐⭐⭐ | Full | All book types | ✅ Best |
| HTML | ⭐⭐⭐⭐ | High | Tech-comfortable authors | ✅ Very good |
| DOCX | ⭐⭐⭐ | Limited | Simple text-only books | ⚠️ Works |
| MOBI | N/A | N/A | Deprecated 2022 | ❌ Do not use |
EPUB is Amazon’s officially recommended format for Kindle eBook uploads. It gives you the cleanest, most predictable conversion to Kindle’s internal KFX format. The fastest path to a properly formatted EPUB is: write in Word → export to PDF → use our free Kindle HTML Converter → open the HTML in Calibre → export as EPUB → upload to KDP.
Kindle Cover Requirements & Ideal Dimensions
Your Kindle eBook cover is separate from your paperback cover. It is a single flat image — no spine, no back cover. The cover for a Kindle eBook formatting guide should meet these exact specifications to display sharply on Amazon’s product page and on all Kindle devices.
| Spec | Minimum | Ideal | Best Quality |
|---|---|---|---|
| Width | 625 px | 1,600 px | 2,500 px |
| Height | 1,000 px | 2,560 px | 4,000 px |
| Ratio | 2:3 portrait | 2:3 portrait | 2:3 portrait |
| Format | JPG or PNG | JPG 85%+ | JPG 90%+ |
| Max file size | — | 50 MB | 50 MB |
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Resize Cover Free →Table of Contents — The Right Way
A Kindle table of contents has two components: the navigational TOC (used by the Kindle device’s menu) and the HTML TOC (a clickable page in the book itself). Amazon requires a navigational TOC for all Kindle eBooks. The navigational TOC is generated automatically from your heading tags if you upload EPUB or HTML — make sure you use H1 and H2 tags consistently for chapter titles throughout your Kindle eBook formatting.
For books uploaded as DOCX, Amazon generates the TOC from Word’s built-in heading styles. Apply the “Heading 1” style to all chapter titles before uploading — do not use manual bold or larger font size as fake headings, as these will not be recognized. The Kindle HTML Converter handles TOC generation automatically from your PDF structure.
Metadata — What Actually Drives Kindle Discovery
Your Kindle eBook metadata — title, subtitle, author name, description, keywords, and categories — is what Amazon uses to rank your book in search results and recommend it to readers. This is where most first-time authors invest too little effort. The Kindle eBook formatting guide principle here is: perfect formatting with poor metadata will underperform a moderately formatted book with excellent metadata.
Your 7 backend keyword fields each hold up to 50 characters and should contain complete search phrases, not single words. Use our free KDP Keyword Tool to find real Amazon search phrases in your genre. Your book description should lead with a compelling hook, not a summary — readers decide in seconds whether to buy.
File Size and Kindle Delivery Fees
On the 70% royalty plan for Kindle eBooks, Amazon deducts a delivery fee of $0.15 per megabyte of file size before paying your royalty. A 1MB eBook costs $0.15 in delivery fees. A 5MB eBook with images costs $0.75. For text-only novels, this rarely matters — typical file sizes are 0.3–0.5MB. For heavily illustrated non-fiction, cookbooks, or children’s books, delivery fees can be significant.
Minimize delivery fees by compressing images before embedding them in your EPUB. JPEG images at 70–80% quality are usually indistinguishable from full quality at screen resolution. Remove any embedded fonts that aren’t essential. The 35% royalty plan has no delivery fee, which is why some authors with large image-heavy books choose that plan despite the lower percentage.
Previewing Before Publishing
Always preview your Kindle eBook using KDP’s online previewer before clicking Publish. The previewer simulates your book on Kindle Paperwhite, Kindle Fire, and the Kindle phone and tablet apps. Check that chapter headings appear correctly, the table of contents links work, images display at the right size, and no text is cut off or incorrectly formatted. Fix any issues and re-upload before publishing.
5 Kindle Formatting Mistakes That Cost Authors Sales
1. Uploading at minimum cover size. A 625×1000 px cover looks blurry on modern screens. Always use 1600×2560 px minimum — use our Cover Resizer to get the exact dimensions.
2. No table of contents. Kindle devices show the TOC in the navigation menu. Missing TOC generates reader complaints and bad reviews.
3. Using MOBI. Amazon deprecated MOBI in 2022. Upload EPUB for best results.
4. Ignoring keywords. Empty keyword fields means Amazon cannot match your book to reader searches. Use all 7 fields with real search phrases.
5. Fixed-layout formatting. Kindle uses reflowable text. Trying to lock in specific layouts using fixed positioning or tables produces broken formatting on some devices.