Kindle books are available in a proprietary e-book file format created by Amazon.com called the Kindle File Format (KFF) . E-book files in the KFF originally had the filename extension .azw, but version 8 (KF8) introduced HTML5 & CSS3 features and have the filename extension .azw3. KF8 supports advanced font and layout formatting, making it a more advanced format than MOBI and AZW. Kindle devices can also display some generic document formats such as plain text (TXT) and Portable Document Format (PDF) files, but reflowing is not supported for these file types.
In summary, Kindle books are available in the following formats:
- Kindle File Format (KFF)
- MOBI
- AZW
- KF8/AZW3
- PRC
- EPUB (can be converted to MOBI using third-party software)
- PDF (reflowing not supported)
