In this modern era, knowledge and its access are at the distance of your fingertips. Through internet access, there are thousands of books one can read and make life more wonderful by the knowledge written by spectacular authors. Handheld devices such as smartphones and tablet pcs support several eBook file formats to provide a fantastic way of reading digital books online.

There are different formats available on the internet for reading eBooks (electronic books) online. These formats provide the facility of reading these books and have their specific properties. EBooks can be converted from one format to another e.g. EPUB to PDF. Some of the best eBook formats along with the specifications are discussed in this article.

Top eBook File Fomats


PDF stands for “Portable Document Format”. It was developed by Adobe and is the most commonly used digital file format these days. People are more familiar with the PDF eBook format as compared to other formats. It lacks the property of reflow so it is not considered a true eBook. Due to this format’s ease of access and capacity of maintaining designs and formats of high ends, it is a comparatively more preferred format. This format is considered similar to EPUB but has a unique property i.e these can be easily downloadable and shared for free without loss of data.

AZW and AZW3

AZW format is specified for Kindle readers of Amazon. It was a replacement for the MOBI files. These files use the MOBI format. These have the property of DRM protection, which means that these can be used on Kindle devices and those devices which have installed kindle apps. Moreover, these can be accessed by the online bookstore of Amazon. This format is mostly used on old kindle devices.

AZW3 is another format and it is also specified for Amazon Kindle devices similar to AZW  format. This format was introduced after the development of Kindle Fire and contains properties that are required for a next-generation version of a file of Kindle eBook. This format is also known as Kindle Format 8 and supports HTML and CSS files.


It is also known as the Mobi pocket eBook file. EBook format MOBI was used as the first file format for Kindle. This format lost support from Amazon in 2011 and was replaced by the AZW format. The structure of these files is still used in Amazon Kindle devices with different DRM protection and AZW file extension though these files are more popular but not much used other than Kindle devices.


EPUB stands for “Electronic Publication”. It is a commonly used format for eBooks and contains the property of compatibility with almost all the devices such as PCs, smartphones and tablets, etc. EPUB files are reflowable and are DRM protected. These are secure in copy protection and support fixed layouts. Though there are differences between EPUB and PDF file formats, EPUB files can be converted to PDF.


A simple text file is a document that contains text-only data and has the .txt extension. TXT files are specified for the text representation. Images and graphs are not supported by this file format. They do not comprise fixed layouts or digital rights management protection. These are also best for the text-only files that have no formatting except font styles.

What are the Contents of an eBook?

If you are going to include only text format in your book, then the PDF and TXT format will be best for the book. For those books which have graphics or interactivity, the choice should be fixed layout EPUB or PDF. It has compatibility with all of the devices and would be great for the representation of graphics and designs. Hopefully, now you have eBook formats explained.

How to Choose the Right eBook Format?

Several aspects should be kept in view before choosing the right eBook format. The issues in the way of selection and publication can be solved by keeping some basic aspects in mind. You should consider the following points

  • Who is your targeted audience? The people you are writing or publishing for are either kids, adults, or parents only. One should keep this thing in his consideration.
  • What content are you choosing for the book? It deals with the design or pattern of the book. If the book comprises images and graphics or includes only plain text then which eBook format will be good.
  • The place (either website or any online eBook retailer) where you are going to publish your book should be considered as an important thing.

Final Verdict

The information and aspects discussed above would be best for anyone who is going to publish an eBook. The eBook formats comparison has been done in the article. A format should be chosen for an eBook according to the content of the eBook. Another very considerable aspect is that the eBook formats android audience must be kept in mind before publishing, choosing content, and eBook format.