Kindle e-books are encoded in AZW format or a variant thereof. The Kindle Reader also supports e-books in TXT, MOBI and PRC formats. While your Kindle device has no problem displaying text documents, you may want to convert them to AZW or MOBI format for various reasons. Free e-book converters can encode a wide selection of formats as Kindle files, and some of these converters offer features such as font scaling and the automatic detection of a book's structure, including its table of contents and chapters.

Step 1

Download and install a free e-book converter, such as Calibre, Hamster E-Book Converter or Auto Kindle E-Book Converter (links in Resources). These programs vary widely in the features they offer, with Calibre the most full-featured and Auto Kindle E-Book Converter the least. Choose Calibre if you want a full e-book manager and don't mind a large application size. Choose Hamster or Auto Kindle E-Book Converter for a small file size and few features.

Step 2

Launch your e-book converter and select a file to convert. If you are using Calibre, you must add a book to your library by clicking “Add Books” and selecting a file from your computer. If you are using either of the other two converters, click “Add” and select a text file.

Step 3

Click “Convert” or a similar option, depending on your software. If you are using Hamster, select the “Amazon” tab, click “Select Format” and choose “AZW” or “MOBI” from the drop-down menu. If you are using Calibre, a pop-up window opens and displays a large number of conversion options, organizing them by categories in a sidebar. Select the “Look and Feel” tab, click the “Output Format” menu and choose “AZW” or “MOBI” from the list. Select the “Page Setup” tab and choose “Kindle” from the Output Profile menu. If you are using Auto Kindle E-Book Converter, your only option is to convert the file to MOBI format.

Step 4

Click “OK” or “Convert,” depending on your software. If you are using Hamster or Auto Kindle E-Book Converter, your converted file is saved in the same folder as the original file. If you are using Calibre, your converted file is saved in the Calibre Library folder in your Documents directory. You can load the converted file on your Kindle by connecting your device to your computer with the included USB cable and copying the file to the Documents folder on your Kindle. You may need to restart your device before it recognizes the new file.