How to convert EPUB to MOBI or AZW3

Most eReaders support the EPUB format so they’re perfect for sharing, but unfortunately, they can’t be read on Amazon Kindle devices. To read your EPUB eBook on a Kindle you must first convert it to an Amazon proprietary standard such as MOBI or the newer AZW3 format. AZW3 is an updated and more sophisticated form of MOBI that works on all modern Kindles.

The main difference between the EPUB open format and the Amazon proprietary formats is that typically MOBI and AZW3 files are protected by Digital Rights Management, or DRM, which locks down your eBook to a specific device associated with your Amazon account.

Best Conversion Tools

To convert your EPUB to MOBI or AZW3, we recommend one of the following tools:

  1. Epub2kindle.com is a great free online option that’s specifically designed for converting EPUB to AZW3. Just drag-and-drop one or more EPUB files and once it’s converted simply click download. Several languages are supported.

    epub2kindle.comepub2kindle.com languages


  2. Zamzar.com is a free multi-file conversion site so you can choose to convert your EPUB to MOBI or AZW3. Simply add your EPUB files, select the conversion format such as MOBI or AZW3, and click convert now.

    ZamZar.comZamzar.com convert to


  3. if you want a great free offline solution, we recommend you install Calibre. Calibre is an open-source completely free eBook manager capable of converting to and from many eBook formats types including EPUB to MOBI and AZW3. Once you added an EPUB to your library, just click the convert books icon on the ribbon menu.

    Calibre eBooks

Now that you’ve converted your EPUB to MOBI or the AZW3 Kindle format, check out our in-depth article on How to Send eBooks to Your Kindle.

EBook Formats

Here’s a bit more detail on eBook formats:

  • EPUB: A vendor-neutral, open-standard and by far the most ubiquitous eBook format. Supported by almost all eBook readers except Kindle i.e. Nook, Kobo, Sony Reader etc, an EPUB is really an archive of Web Standards including HTML, CSS, images, and SVG. In EPUB 3, even Javascript code, audio and video assets can be added. EPUB eBooks can optionally be protected using a DRM scheme such as Adobe’s ADEPT DRM.

  • MOBI: Just like EPUB, MOBI is also derived from the old OEB format. They use similar components, although unlike EPUB, MOBI is an Amazon-owned proprietary format originally developed for the Mobipocket Reader. Also like EPUB, these days most of the MOBI eBooks are DRM-free. However, if Amazon converts them to AZW3 then they are likely to be protected by their DRM scheme.

  • AZW3: Also known as KF8 or Kindle Format8, this format was released alongside the Kindle Fire. It contains more complex formatting options than MOBI as well as considerable performance improvements. You an expect the archive files to considerably smaller in size. This is the most popular format for most of the current Amazon Kindle devices, although AZW4, AZW6, and the most advanced AZW8 format, are all out there.

One last thing before we go. Although not specifically designed for converting eBook formats, it is also possible to use the free Amazon Kindle Preview desktop application to convert your EPUB to MOBI or AZW3. It’s an app for authors and publishers to preview how their books will appear on Kindle devices, but you can use it to convert between eBook formats. Follow this video tutorial to find out how.



Explore thousands of free audiobooks and ebooks at digitalbook.io.

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