EPUB vs Mobi: Which eBook format to use?

epub vs mobi

Reading in the screen age has changed dramatically. We are no longer confined to the pages bound between the covers of printed books. In this digital age, books no longer have to be heavy or bulky. In fact, an eBook doesn’t have weight, dimensions, or any other real physical attributes. However, what it does have arefile types and file sizes. A well formatted eBook becomes reading material, and is properly displayed on the right device or screen.

eBook Formats

 eBooks come in several formats, but there only a few that stand out as favorites. The most used file formats for eBooks are

  • PDF
  • MOBI
  • EPUB

For comic books and graphic novels, the most popular file type is fixed Layout. Read more to find out which is the best option for your book!

An eBook comes in many different file formats. Each of which will require their own compatible reader. The right eBook reader will translate the bits of data found in the eBook file and display them as words or pictures on the screen. The result will be a virtual book page that you can read as you would a physical, paper book page.

Though what you see on screen might be similar to a physical page, you’ll now have more ways of interacting with it. You can change the font style, font size, page size, backlight intensity, and so much more. With the latest eBook technologies, you can even enjoy complementing media embedded into the pages such as music, audio, and animation for a more engaging and immersive reading experience. These interactive functionalities add a whole different level of enjoying your book titles that’s not possible with physical books.

What is EPUB?

what is epub

EPUB stands for Electronic Publication. It is a well-known open digital format for storing eBooks that anyone can use. There are plenty of EPUB eBook readers available online for mobile and desktop users. Sadly, Kindle is not one of them. Kindle has made it a point not to include EPUB as a valid file type for their Kindle devices. This is a business move that protects their bottom line by essentially forcing Kindle users to use and purchase eBooks formatted using the exclusive proprietary Kindle file types. However, there are a few ways to circumvent this problem. The most popular method is with the help of a free open-source eBook reader to convert EPUB books to the valid Kindle file format.


epub 3

EPUB3 is the latest innovation of this eBook format standard. It utilizes a lot of new interactive features that are provided by web standards such as HTML5 and CSS3. One of the most important of these interactive functions is the read aloud function wherein words on the page are read aloud. Other interactive features that enhance the reading experience include pop up definitions of words, narrations, music and audio, and even animated illustrations.

EPUB3 is capable of using both reflowable and fixed layout for eBooks. Reflowable format means that elements such as text and images are no longer fixed on the page. This is an especially important feature since different reading devices have different screen sizes. With the reflowable layout, no element is pushed out of the screen. Everything adjusts automatically to fit the screen display for an effective reading experience. EPUB3 also allows media overlays and changeable elements such as adjustable file styles and size.

The Fixed-layout eBook is “fixed” and static. You cannot make changes to the layout. This means that you’re stuck with the font style and size. Depending on screen size, some elements such as images and words may be pushed off screen. To view these, you must scroll or zoom in and out of the page. Even with fixed layout, if the eBook utilizes the EPUB3 standard, interactive features are still supported.

What is MOBI?

A .MOBI file is an eBook format that was developed by Mobipocket. It’s the file format that all current Kindle formats are based on. All Kindle readers can still display MOBI eBooks even without conversion. The MOBI file supports the addition of notes, bookmarks, and even corrections.

KF8 or AZW3

The KF8 is the latest version of the MOBI-based proprietary file format. It now supports the HTML5 and CSS3 web standards. This allows for more complex book layout designs. KF8 files are also backward compatible with older generations of Kindle since they are compiled with a .MOBI version.

What is a Book PDF?

A PDF is a popular file format that serves as an archive for digital copies of documents. PDF stands for Portable Document File, which clearly describes what it is. Being an electronic version of a document, this particular file type lends itself well to books. You can have a PDF version of a physically published book by scanning it or having the source Word document published as a PDF file.

PDFs are popular because they are lightweight archives that can be opened on desktops, laptops, or mobile devices. You simply need to have a PDF reader installed, such as the pioneer Acrobat Reader.

What is the Best Format for an eBook?

In terms of accessibility and popularity, there are three main formats: PDF, EPUB, and the Kindle MOBI formats. In terms of features, there are no clear winners since most of these formats have very similar functionalities.


epub and mobi formatting

EPUB and MOBI are the two competing, most widely used eBook standard formats in the world. The main difference is that EPUB is an open standard that was developed and continuously maintained by the IDPF or the International Digital Publishing Forum, while MOBI is a proprietary technology owned by Amazon through its acquisition of Mobipocket.

MOBI is the format on which Amazon based all of its Kindle eBook file formats while EPUB is used by every other eBook reader. EPUB files can be read by most eBook readers except for Amazon’s Kindle. Kindle makes it a point to not include EPUB in its supported file formats. Both have similar functionalities.

Their most recent versions, KF8 for MOBI and EPUB3 for EPUB, have much more improved interactive functionalities and are both able to display reflowable and fixed layout content. Both support HTML5 and CSS3.

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