A file with the .azw file extension is a popular file format for storing eBooks for Amazon’s Kindle line of eReaders and devices using the Kindle app. Along with storing things like bookmarks, annotations, and last known page, AZW files usually contain DRM protection, or copyright protection, to prevent copying and illegal viewing.

What Is an AZW File?

AZW files first rolled out onto Kindle devices in 2007; it’s based on the MOBI file format that Amazon bought in 2005. Although AZW files are based on MOBI, they contain better compression than MOBI files and are usable on Amazon Kindles or a device with Kindle software.

Fourth generation and later Kindles use the AZW3 format, also called KF8, while seventh generation and later Kindles use KFX format.

RELATED: What Is a MOBI File (and How Do I Open One)?

How Do I Open One?

Since AZW files are designed for Kindle, the easiest way to open one is on a Kindle device or with the Kindle app on WindowsMac, iOS, or Android.

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If you’re using Linux, you’ll have to turn to a third-party reader like Calibre. It’s an open-source app that offers enough versatility that you might even prefer using it on Windows and macOS, as well. Calibre can open AZW files, as well as many other formats.

All you have to do is open the program, click “Add Books,” and then select how you want to add your books.

A couple of other options would be to send those files to your Kindle using the Send to Kindle app, using a USB cable, or by email. Anything sent is held in your Kindle Personal Documents online, where they are kept and are restored from when you buy a new Kindle.

RELATED: How To Send eBooks & Other Documents To Your Kindle

How Do I Convert One?

Just like any other file format, you need specialized software to handle converting AZW into a different format. If you try to change the extension, you could wind up with a corrupt and unusable file.

Along with being an eReader, Calibre comes with a handy conversion tool that can convert any of your eBooks into 16 different formats. Converting from AZW first requires your files to be DRM-free, so for this example, we will be assuming your files have no DRM associated with them.

RELATED: How to Strip the DRM from Your Kindle Ebooks for Cross-Device Enjoyment and Archiving

Open up Calibre, select the book you want to convert, and then click “Convert Books.”

In the conversion window that opens, select the output format you want and then click “OK” at the bottom of the window.

The converted file is stored in your library on your local drive. Available formats are displayed in the preview pane of each book.