Kindle Format 8 Now Out of Beta – Go Get it!

Amazon announced today that they were making the tools and specs for their new ebook format available to the public. You can go download the files now, and start making ebooks that only work properly on the Kindle Fire. Sorry, but given the excitement this will generate I thought it best to puncture the hype.

Well, that was a short beta test. Amazon only first mentioned KF8 back in October, shortly before the Kindle Fire shipped. And I've only had my hands on the beta for just over a month. And now everyone has it.

(For more details on Kindle Format 8, click the 2 links above. )

Amazon is now going to let you submit an ebook with more complex formatting, but to be honest they've been doing that for over a year. Back in the fall of 2010, amazon distributed a new version of KindleGen that (whenever the source was Epub) started hiding the Epub in the back of the AZW file it made. At the time we all guess that they were planning ahead for something, and the Epub supporters were hopeful  that Amazon might switch over to the better format. Well, we know that's not going to happen.

By all means, start learning how to use it.  But when you do adopt it, it's going to mean an increase in some people's workloads in the short term.

Back when I converted ebooks for a living, I leveled out my Epubs at about the same level of formatting found in the Kindle format.  Doing a second ebook for the more sophisticated Epub format would have added more to the cost than most authors wanted to pay (and I mainly did novels, which don't usually have complex formatting).

If you start using the new features found in KF8 now, you're going to have to also continue to make a less complex AZW file, because none of the apps or devices support the new features. If you don't then your ebooks will look bad to most of your readers.

In any case, here are the download links:


Kindle Previewer

Kindle Publishing Guidelines

If you're in a hurry, just get the previewer. It can make a KF8 file from an Epub. And once you have the tools, please come tell me what you think. I want to hear your opinion.


About Nate Hoffelder (11466 Articles)
Nate Hoffelder is the founder and editor of The Digital Reader: "I've been into reading ebooks since forever, but I only got my first ereader in July 2007. Everything quickly spiraled out of control from there. Before I started this blog in January 2010 I covered ebooks, ebook readers, and digital publishing for about 2 years as a part of MobileRead Forums. It's a great community, and being a member is a joy. But I thought I could make something out of how I covered the news for MobileRead, so I started this blog."

5 Comments on Kindle Format 8 Now Out of Beta – Go Get it!

  1. nate, the previewer link isn’t working for me

    the previewer will convert epubs to the new format?


    • I fixed the link.

      And yes, the previewer will convert Epub into Kindle. It has for a while now.

      • thanks nate, yea got the new previewer

        the old one, i never got it to work for me, so i used apple’s pages then converted by file to epub which then i converted to mobi via calibre, and have had great success that way

        the new previewer does open my epub files, but doesn’t recognize either my toc or my cover –

        but did output a mobi file “with warnings”

        and was able to show me several “looks” on various devices, which was kinda interesting

        i’m actually hoping calibre will stay on it and eventually be able to do my mobi and kf8 conversions

        btw, the epub file the new previewer read and didn’t recognize the toc & cover on, passed epub check

        all in all, very interesting 😉 thanks again

    • The output of these tools is a .mobi file that in most cases contains both KF8 and mobi formats (as well as an archive of the source files fed to it). That gets submitted to Amazon, and when a customer requests a book, they deliver the format appropriate to the device or app in question.

      You use Media Queries to fine-tune the output for one or the other format. But that requires editing source files (at least a CSS file), not just feeding an ePub into the meat grinder. Ironically, they point to the ePub3 spec when directing you how to set up the source files. The mbp: tags are gone.

      It is especially interesting to open the ‘KF8’ sample file, and compare the Previewer results in ‘Kindle’ and ‘Kindle Fire’. They are not using any Media Queries to fine tune the mobi result, which is in fact quite ugly.

      Clearly there will be cases (fixed layout for example) where there should be NO mobi format. But the tools don’t seem to make any such distinctions. I wonder how Amazon plans to deal with this.

      Finally, I wonder which Kindle eInk devices will be get a KF8 update, when that will happen, and in particular if K3/KindleKeyboard makes the cut. I’ve been assuming ‘not’ but given the downside to having such a large install base for the next few years with the significant potential for even worse formatting than usual, I hope I’m wrong and that it is something Amazon will do if it is technically feasible.

  2. Just played around with the new kindlegen and KF8 using Project Gutenberg “free” [out of copyright] files. Project Gutenberg has the problem that they require HTML as their “book” file submission format — they refuse to accept EPUB nor MOBI files. And then people who think they know how to write HTML submit HTML files which are not much good for either EPUB nor MOBI reader devices. And then Project Gutenberg tries to munch on the submitted HTML to make it somewhat more friendly for EPUB and MOBI devices — without a great deal of luck. A better solution now it looks to me is if someone is interested in reading a Project Gutenberg “book” on Kindle Fire then download the HTML version and run it through the new kindlegen yourself. You may now have to “fix” some things in the HTML that kindlegen used to ignore entirely — such as when HTML writers set left and right margins in the “body” style specification — yuck! One can just quickly edit out these kinds of big, global, errors in the HTML code, and end up with something that is pretty happy and attractive on a Kindle Fire. Unfortunately, as you suggest, just because some feature is now “fixed” for the Kindle Fire doesn’t mean that it is “fixed” for other versions of the Kindle. For example one common problem in HTML files is that HTML authors often “split the baby” by setting a paragraph top margin of 0.5 em, and a bottom margin of 0.5 em, expecting to get a merged 0.5 em spacing between paragraphs. This now “works” on the Kindle Fire when compiled using the new kindlegen. View that same file however, on an older Kindle and one still sees 2.0em spacing between these same paragraphs! You get 2.0em spacing between paragraphs because 1) older Kindles do not merge top and bottom margins and 2) They round top and bottom margins to the closest 1.0em — so the 0.5em specs get rounded up to 1.0em — and then get added together — resulting in paragraph spacing 4X that which was requested. See: for a demonstration of this problem.

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