By using one of these methods, you should be able to convert a KFX-ZIP file to EPUB. Keep in mind that eBook conversion can sometimes be imperfect, especially with complex layouts or DRM-protected content.

Import the KFX-ZIP file into Calibre. If the DeDRM plugin is configured correctly (using your Kindle's serial number or Kindle for PC keys), Calibre will automatically strip the DRM upon import and display the format as rather than KFX-ZIP. Convert to EPUB: Right-click the book in your library, select Convert books Convert individually , and set the Output format in the top right corner to Save the File: