What KDP Accepts — and the March 2025 Format Change

KDP accepts EPUB, DOCX (Word), HTML, and KPF (Kindle Package Format from Kindle Create). As of March 2025, KDP no longer accepts MOBI files for any ebook uploads — this completes the full deprecation of the MOBI format that began in 2021.

🚨 IMPORTANT:  MOBI files are no longer accepted by KDP as of March 18, 2025. If you have been uploading MOBI files, switch to EPUB immediately. EPUB is now the recommended format and produces the most reliable Kindle conversion.

EPUB is the best choice for most authors: it is the industry-standard ebook format, produces clean Kindle output, and is what professional formatting tools (Vellum, Atticus, Scrivener's compile function) produce by default. Word (DOCX) files also upload successfully but are more prone to unexpected styling issues during KDP's conversion process.

The Most Common Formatting Errors

1. Broken or missing Table of Contents

Kindle readers expect to be able to tap a chapter title in the TOC and jump there instantly. If your TOC doesn't work — or doesn't exist — it's one of the first things readers notice and comment on in reviews. The cause is almost always using visual formatting (large, bold text) instead of proper Word heading styles. Fix: format every chapter title as Heading 1 in your Word document before converting to EPUB. The EPUB generator builds a functional TOC from heading styles, not from text that looks like a heading.

2. Curly quotes and em-dashes turning into question marks or boxes

This happens when your file is saved without explicit UTF-8 encoding declaration — KDP's conversion engine misinterprets certain characters. Fix: in Word, ensure your document is saved as DOCX (not older .doc format). When using an EPUB converter, verify UTF-8 encoding is selected in the export settings.

3. Blank pages between chapters

One of the most frequently reported reader complaints. Caused by extra paragraph marks, manual page breaks stacked on automatic chapter breaks, or section breaks that conflict with the EPUB's own chapter structure. Fix: in Word, use Find & Replace to locate and remove multiple sequential paragraph marks (search for ^p^p and replace with ^p). Rely on chapter break formatting in your software rather than stacking manual page breaks.

4. Images not displaying correctly

Images in ebooks need to be below a certain file size (generally under 5 MB each and 650px wide maximum for standard Kindle display), in RGB colour mode (not CMYK), and saved as JPEG or PNG. Images that are too large cause slow page loading and can cause reflowing issues on older Kindle devices.

5. Custom fonts not appearing

Kindle readers can choose their own font in device settings, which often overrides embedded fonts. Authors who embed custom fonts are frequently disappointed to find readers see Bookerly (Amazon's default Kindle font) instead. Embed fonts if you wish, but design your book to look good in the default Kindle fonts as a baseline.

💡 TIP:  The single most effective thing you can do before uploading to KDP: download the free Kindle Previewer application from kdp.amazon.com/en_US/help/topic/G200234840 and preview your file on multiple simulated Kindle devices. The Phone, Tablet, and Kindle E-reader simulators all render slightly differently. If it looks right in all three, it will look right to your readers.

The Word Styles Approach — The Fix That Prevents Most Problems

Most ebook formatting problems originate in the same place: a Word document that used visual formatting (manually adjusting font size, bold, spacing) instead of paragraph styles. KDP's conversion engine reads styles, not visual appearance. A chapter title that looks like a heading because it's big and bold, but has 'Normal' style applied, produces a flat, unsearchable ebook without a working TOC.

1. In Word: go to Home > Styles panel. Apply 'Heading 1' to every chapter title

2. Apply 'Heading 2' to any section subheadings within chapters

3. Apply 'Normal' style to all body text — do not manually set font or size on body paragraphs

4. Remove all manual page breaks from the body — use Heading 1 to trigger chapter breaks instead

5. Use Find & Replace (Ctrl+H) to find double paragraph marks (^p^p) and replace with single marks (^p)

6. Save as DOCX and run through Kindle Previewer before uploading

Using the Kindle Previewer

Download Kindle Previewer free from Amazon's KDP help pages. Open your EPUB or DOCX file in it and check: does the Table of Contents work? Does the chapter navigation panel show all chapters? Do images display correctly? Are there unexpected blank pages? Do the first few pages of every chapter look right?

Previewer has simulators for Phone, Tablet, Kindle Paperwhite, and older Kindle devices. Check at least Phone and Paperwhite — they have different screen sizes and render text differently. A common discovery: images that look fine on the tablet simulator are too wide for the phone view.

💡 TIP:  The Previewer also flags errors in its log panel — a list of technical EPUB issues it detected. Many of these are harmless warnings, but anything labelled 'Error' (as opposed to 'Warning') should be investigated and fixed before uploading.

How ScribeCount Helps

Once your ebook is live on KDP and formatted correctly, ScribeCount's Sales Dashboard tracks its daily performance — units sold, KENP page reads for KU-enrolled books, and royalties — alongside all your other platforms. A well-formatted ebook earns better reviews and better read-through rates, which show up over time as more stable sales curves in ScribeCount's Historical view.