Kindle File Format
{{Short description|E-book file format}}
{{Infobox file format
| name = Kindle File Format
| icon =
| screenshot = 150px
| logo =
| caption =
| extension = .azw, .azw3, .kfx
| mime = application/vnd.amazon.mobi8-ebook
| type code =
| uniform type =
| magic =
| owner = Amazon.com
| released = 2007
| latest release version = 10
| latest release date = 11 August 2015
| genre = e-book file format
| container for =
| contained by =
| extended from = HTML5, CSS3, MOBI
| extended to =
| standard =
| open = No
| url =
}}
Kindle File Format is a proprietary e-book file format created by Amazon.com that can be downloaded and read on devices like smartphones, tablets, computers, or e-readers that have Amazon's Kindle app. E-book files in the Kindle File Format originally had the filename extension .azw;{{efn|.azw expands into AmaZon Word}} version 8 (KF8) introduced HTML5 & CSS3 features and had the .azw3 extension; and version 10 introduced a new typesetting and layout engine featuring hyphens, kerning and ligatures and has the .kfx extension.
History
Kindle devices and apps are designed to use Amazon's e-book formats: AZW that is based on Mobipocket; in fourth generation and later Kindles, AZW3, also called KF8; and in seventh generation and later Kindles, KFX.{{cite web|url=https://www.zamzar.com/fileformats/azw3|title=AZW3 file - Zamzar - Free online file conversion|access-date=2017-08-15|archive-date=2019-04-18|archive-url=https://web.archive.org/web/20190418102418/https://www.zamzar.com/fileformats/azw3|url-status=live}} Similar to EPUB, Amazon's file formats are intended for reflowable, richly formatted e-book content and support DRM restrictions, but unlike EPUB, they are proprietary formats. AZW files debuted with the first Amazon Kindle in 2007.
Software such as the free and open source Calibre, Amazon's KindleGen,{{cite web |url=http://www.amazon.com:80/gp/feature.html?ie=UTF8&docId=1000234621 |archive-url=https://web.archive.org/web/20110815083555/http://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000234621 |url-status=dead |archive-date=August 15, 2011 |title=Kindle Publishing Programs |publisher=Amazon.com |date=July 12, 2011 |access-date=August 15, 2011 }} Now via Internet Archive.{{cite web |url=https://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000765211 |title=KindleGen |publisher=Amazon.com |access-date=February 7, 2019 |archive-date=September 5, 2019 |archive-url=https://web.archive.org/web/20190905040839/https://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000765211 |url-status=live }} and the email based Send-to-Kindle service are available to convert e-books into supported Kindle file formats. Kindle devices can also display some generic document formats such as plain text (TXT) and Portable Document Format (PDF) files; however, reflowing is not supported for these file types.
In late 2011, the Kindle Fire introduced "Kindle Format 8" (KF8), also known as AZW3 file format.[https://www.amazon.com/gp/feature.html?docId=1000729511 Kindle Format 8] {{Webarchive|url=https://web.archive.org/web/20170329160904/https://www.amazon.com/gp/feature.html?docId=1000729511 |date=2017-03-29 }}, Amazon.com, October 2011. AZW3 supports a subset of HTML5 and CSS3 features,{{cite web|title=List of supported HTML tags and CSS elements|url=https://www.amazon.com/gp/feature.html/ref=amb_link_357613442_1?ie=UTF8&docId=1000729901&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-5&pf_rd_r=1SMP3WA2ZFPE1V88B33V&pf_rd_t=1401&pf_rd_p=1321300302&pf_rd_i=1000729511|publisher=Amazon|access-date=4 August 2012|archive-date=14 December 2019|archive-url=https://web.archive.org/web/20191214232547/https://www.amazon.com/gp/feature.html/ref=amb_link_357613442_1?ie=UTF8&docId=1000729901&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-5&pf_rd_r=1SMP3WA2ZFPE1V88B33V&pf_rd_t=1401&pf_rd_p=1321300302&pf_rd_i=1000729511|url-status=live}} while acting as a container for a backwards-compatible MOBI content document.{{cite web|url=https://digitalpubbing.com/the-new-kindle-format-8-kf8|title=The New Kindle Format (KF8)|author=Sabrina Ricci|publisher=Digital Pubbing|date=March 6, 2012|access-date=September 29, 2018|archive-date=April 23, 2019|archive-url=https://web.archive.org/web/20190423033921/https://digitalpubbing.com/the-new-kindle-format-8-kf8/|url-status=live}}[https://techcrunch.com/2011/10/20/amazon-throws-a-minor-curveball-with-html5-kindle-8-format "Amazon Throws A Minor Curveball With HTML5-Powered Kindle Format 8"] {{Webarchive|url=https://web.archive.org/web/20170815185352/https://techcrunch.com/2011/10/20/amazon-throws-a-minor-curveball-with-html5-kindle-8-format/ |date=2017-08-15 }}, TechCrunch, October 20, 2011.
In August 2015, all the Kindle e-readers released within the previous two years were updated with a new typesetting and layout engine that adds hyphens, kerning and ligatures to the text; e-books that support this engine require the use of the "Kindle Format 10" (KFX) file format.[https://the-digital-reader.com/2015/08/11/kindle-ebooks-with-improved-typography-use-new-kfx-file-format Kindle eBooks with Improved Typography Use New KFX File Format] {{Webarchive|url=https://web.archive.org/web/20190418102728/https://the-digital-reader.com/2015/08/11/kindle-ebooks-with-improved-typography-use-new-kfx-file-format/ |date=2019-04-18 }}. Retrieved 11 August 2015 E-books that support the enhanced typesetting format are indicated in the e-book's description on its product page.
In 2017, Amazon released Kindle Create, a tool that can convert Microsoft Word files to Kindle file format.{{cite web|url=http://epubsecrets.com/kindle-create-a-new-ebook-conversion-tool.php|title=Kindle Create: A New Ebook Conversion Tool|date=April 6, 2017|website=EpubSecrets|access-date=February 25, 2020|archive-date=February 25, 2020|archive-url=https://web.archive.org/web/20200225053159/http://epubsecrets.com/kindle-create-a-new-ebook-conversion-tool.php|url-status=live}}
In 2022, while the Send-to-Kindle service only supported the original .mobi/.azw ebook formats (along with some other non-ebook file formats),{{cite web|url=https://www.amazon.com/gp/help/customer/display.html/ref=hp_pdoc_main_short_us?nodeId=200767340|title=Learn About Sending Documents to Your Kindle Library|website=Amazon|access-date=2022-05-04|archive-date=January 25, 2022|archive-url=https://web.archive.org/web/20220125031356/https://www.amazon.com/gp/help/customer/display.html/ref=hp_pdoc_main_short_us?nodeId=200767340|url-status=live}} Amazon announced removing this support in favor of .epub which will be converted to Amazon's KF8 (.azw3) from late-2022.{{Cite web|url=https://goodereader.com/blog/kindle/the-amazon-kindle-will-support-epub-in-late-2022|title=The Amazon Kindle will support EPUB in late 2022|publisher=Good E-Reader|author=Michael Kozlowski|date=April 30, 2022|access-date=May 7, 2022|archive-date=May 4, 2022|archive-url=https://web.archive.org/web/20220504105242/https://goodereader.com/blog/kindle/the-amazon-kindle-will-support-epub-in-late-2022|url-status=live}}{{cite web|url=https://michaelcavacini.com/2022/05/04/amazon-kindle-will-support-epub-books-abandoning-mobi-format|title=Amazon Kindle Will Support EPUB Books, Abandoning MOBI Format|author=Michael Cavacini|website=michaelcavacini.com|date=2022-05-04|access-date=2022-05-04|archive-date=2022-05-04|archive-url=https://web.archive.org/web/20220504113326/https://michaelcavacini.com/2022/05/04/amazon-kindle-will-support-epub-books-abandoning-mobi-format/|url-status=live}}
Footnotes
{{notelist|1}}