Amazon Kindle Format 10 ebook format with enhanced typography, reflowable content, metadata, and optional DRM
File type: E-book file
KFX is a proprietary ebook format used by Amazon Kindle devices and reading applications. Also known as Kindle Format 10, it supersedes the older AZW3 format and supports reflowable text, enhanced typography, flexible layouts, metadata, and advanced reading features.
KFX books are normally opened with Amazon Kindle software on Kindle e-readers, Windows, macOS, Android, iOS, and Fire devices. Support for an individual file depends on its KFX variant, associated resources, and whether it is protected by Amazon DRM.
Found 2 different file type records with the same kfx filename suffix.
File type category:
E-book file
Date updated: August 14, 2026
Unlike a simple, universally documented document format, KFX commonly uses related resources and internal data structures to store ebook content. These may include images, fonts, metadata, reading-position information, and instructions for layout and rendering. A standalone file may therefore require companion files or Kindle-specific processing.
Amazon introduced KFX to improve on earlier Kindle formats with more sophisticated typesetting, font handling, layout control, and support for features such as interactive content, pop-up footnotes, enhanced typesetting, page synchronization, and accessibility information. The exact capabilities vary between titles and devices.
KFX content is generally downloaded and managed through an Amazon account on a registered Kindle device or supported Kindle application. Official Kindle apps for Windows, macOS, Android, iOS, and Fire OS can display compatible books. Kindle books can also be read through Amazon's browser-based reading services where available.
Some DRM-free KFX variants can be inspected or processed with calibre and community-developed KFX plugins, but compatibility is incomplete. DRM-protected books generally require Amazon's software and account authorization, and removing or bypassing DRM may violate copyright law or the applicable terms of service.
The most reliable way to open a KFX book is to download it through the official Kindle application or directly to a registered Kindle device. On Windows or macOS, install the Kindle app, sign in with the Amazon account that owns the book, and download it from the library. Android, iPhone, iPad, and Fire devices can use their corresponding Kindle applications.
Linux does not have a current official Kindle desktop application, so use Amazon's browser-based Kindle reading service where available. For a DRM-free file, try importing it into calibre with compatible KFX support; results vary by KFX variant, and files copied from a Kindle may require companion resources.
KFX is not a convenient interchange format, and general online converters do not reliably support it. For DRM-free books, calibre with suitable KFX input or output support may convert content to or from formats such as EPUB, AZW3, MOBI, or PDF, although enhanced typography, interactive features, and layout may be lost. Some desktop ebook tools can process compatible, unprotected KFX resources.
DRM-protected KFX books generally cannot be converted by legitimate third-party tools. The authorized alternatives are to obtain an EPUB, PDF, or other edition from the publisher, or to continue reading the book with Amazon's Kindle applications. Avoid uploading private or copyrighted books to online conversion services without permission.
Programs for viewing kfx files:
Microsoft Windows
Apple macOS / Mac OS X
Apple iOS
Google Android
Amazon Kindle
File type category:
Bitmap image file
Date updated: June 23, 2025
The kfx file extension is associated with the Kofax Group, a some kind of picture image editing software probably developed for Atari 8-bit computers.
The kfx file stores bitmap graphics (56x60, mono).
Use XnView to view content of *.kfx files.
XnView is able to export *.kfx files to other formats.
Language
