Right-click the book and select > Convert individually . Set the Output format (top right corner) to EPUB . Click OK .
If you only have one or two files and do not want to install software, online conversion tools are a quick alternative. Recommended Online Tools
You did not enter your Kindle serial number correctly, or the book was downloaded for a different device. Fix: Go to Amazon (Manage Your Content and Devices). Find the device you used to download the book. Copy the serial number exactly (watch for lowercase vs uppercase). Re-enter it in Calibre's DeDRM plugin. Re-add the file.
What do you plan to use for reading the final EPUB?
: Users report that using the plugin's dedicated conversion method preserves valid attributes in the
: The book was downloaded with Amazon's copy protection active.
To use this advanced conversion instead of the default "Convert books" button: Install the Plugin Preferences > Plugins > Get new plugins and search for "KFX Input". Add to Toolbar : Navigate to Preferences > Toolbars & menus , select "The main toolbar", and move "From KFX" from Available Actions to Current Actions. Run Conversion : Select your book in your library, click the new button in your toolbar, and choose "Convert to EPUB" Note on KFX-ZIP : If your file appears in Calibre as a after import, it typically indicates that DRM (Digital Rights Management) was not successfully removed. You must ensure DeDRM tools are correctly configured with your Kindle's serial number
While geared toward PDFs, this can be used to handle KFX conversion tasks, particularly when batch processing is required. Troubleshooting Common KFX Conversion Issues
Now that the file is in your library, you are only a few clicks away from a universal EPUB file. Select your newly imported book in the Calibre list. Click the button in the top toolbar.
Your EPUB is now ready. You can copy it to any device: Kobo, PocketBook, Apple Books, or even a re-flashed Kindle.
Once the book appears in your library, click on it to select it. Click the button in the top menu.
Edit book text, fix typos, or change layouts using EPUB editing software.
Here is the most tested, community‑supported method as of 2025–2026:
Take a moment to review the metadata tabs on the left side of the conversion window: Correct the title, author name, or cover image.
EPUB files run seamlessly on Kobo, PocketBook, and Onyx Boox devices, as well as Apple Books and Google Play Books.
Calibre will pop up an error box stating that the book is locked by DRM, or online converters will simply fail to process the file.
Furthermore, the conversion process serves a vital role in . Technology moves at a relentless pace; if Amazon were to eventually abandon the KFX format or go out of business, files locked in that proprietary shell could become unreadable "bit rot." By converting these files to EPUB, users ensure their libraries remain in a format that is easily parsed by future software. It transforms a fragile, platform-dependent asset into a durable, standardized document.
, which can otherwise break and become unusable in readers like Format Selection : You can force specific outputs, such as , or even extract raw resources into a standard ZIP file. How to Access This Feature in Calibre
Which option do you prefer?
