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Understanding eBook Formats: Which Format is Right for My Book?

Writing an eBook is hard work, but just finishing the book is just one part of the process. Once you have a fully written book, it’s time to create an eBook from your text. Unfortunately, you might be confused by the different eBook formats and have trouble deciding which is right for your needs. That’s why we decided to compare different eBook formats and look at what separates them. Most readers looking to create their books will be most interested in comparing Epub vs.Mobi formats for making their books. That’s why we made sure to include both of these formats in our overview. Take the time to look at the brief explanation of each of the main eBook formats used today, and you’ll have a better understanding of which will work best for your needs.

Simple TXT Books

TXT or .txt is the simplest of all the format options, and it isn’t a very good choice for most eBooks. TXT files only hold text information. There isn’t support for any sort of images, which means that books created in this format must be simple in design. The nice thing about this format is that most devices can read it today. Not only that, but the file sizes for .txt files are very small. Thousands of books in this format could be kept on even a modest-sized drive. This format is too limiting for most people, though, and it’s not really a format that any book publishers are using today. Other than something like a research report that’s going to be distributed freely, .txt files aren’t likely to be used for eBooks at all.

PDF Books

PDF files or portable document format files are heavily used around the world for all sorts of documents. PDFs are good and bad for eBooks and will only work for select individuals. PDF is a file format created by Adobe, but there are loads of different tools available that allow you to create your PDF eBooks today. There are free and premium tools available for you to use. PDF documents are good for print items that include photos and details that are meant to be read at a specific size.

PDF documents can be scaled, but their content can’t be shifted or adjusted in any other way. That means that PDF documents are difficult to view on smaller eBook readers, phones, and compact devices. They’re mostly read on computer screens and large-format tablets today. PDF documents always look the same when displayed, which means you can guarantee you get a document that looks the way you want it to when you decide on this format. It’s important to consider that PDF files can’t be sold in most of the eBook stores today, including Kindle, but they can be sold through different channels online today.


EPUB files or electronic publication files are the most popular today and distributed through the largest number of platforms for use by eBook reading devices. In fact, EPUB or .epub files are sold on most eBook marketplaces other than the Kindle marketplace. EPUB files are DRM protected, which makes them copy protected. The books are offered in a dynamic format and a static format. Reflowable EPUB files have text that moves to different positions along with the screen and images to fit most screen sizes well. This is the format allowed on most eBook marketplaces, and it’s the format that’s supported by most reading devices too.

The static version of EPUB files can be highly detailed and created to maintain the same look all the time. They are more difficult to use on eBook readers, but they work well on larger devices and can even incorporate text-to-speech elements and color-changing words on the screen.


MOBI files or Mobipocket eBook files were the first used by Amazon for its Kindle devices. These files still work on Kindle products today, and the books for Kindle are still formatted the same way, though they have the .azw file extension now. These files work on a range of reading devices, other than Nooks and Sony readers, and they are very similar in structure to EPUB files.


Finally, we have the AZW and AZW3 file formats. These are both proprietary to Kindle and will only work on Kindle devices. These two files can be created using a range of different tools, but they’re only useful if you want to sell on the Kindle marketplace. AZW is the original format used by Amazon after swapping from the MOBI format, but AZW3 is the newest format and includes support for HTML and CSS styling for more advanced formats. Either way, these file types are only good for Kindle books.

Hopefully, after reviewing the different eBook file formats, you have a good idea of which one will work best for you. If you want to make books to sell on Kindle exclusively, the AZW3 format is the best option. If you want to widely distribute your books, you should look into the EPUB and MOBI formats. Fortunately, you don’t have to choose only a single file format today because many tools and services will give you multiple file formats for your book, so you have exactly what you need.