Selling your book as an ebook is an easy way to reach audiences around the world. It is important to understand the different formats that your book can be converted into before conversion and uploading to make sure it’s the correct for the ebook retailer.
What is EPUB 3?
EPUB is a format of file for ebooks. The files end in the extension .epub: great_expectations.epub for example. The epub format is widely used and is compatible with almost all ereaders.
Epub files can be downloaded from ebook stores such as Google Play and can be read on computers and other devices very easily.
The major drawback is that most ereaders are Amazon Kindle which uses .mobi rather than epub.
Features of EPUB files
Epub can be designed as reflowable content or as fixed-layout content. This means that when the file is created there is a choice about whether the text will reformat itself to the screen size of the device which it is presented on, or whether the layout will stay the same regardless of the size of the screen.
Reflowable content is best for books with lots of text as it will allow users to read the book on computer screens as easily as a small phone screen.
Fixed-layout content is suited to designed pages such as illustrated books.
Epub files allow readers to change font sizes and highlight passages easily.
Other EPUB formats
Some retailers prefer (but don’t necessarily insist) on changes to the standard EPUB format. Google Play, Kobo, Apple, and Nook are examples. However, they all handle EPUB files with ease, so it’s not necessary to upload platform-specific ebook files.
What is MOBI?
Amazon prefers files formatted to their specifications: a .mobi or .kfx format.
These formats offer the same functionality as epub and allow readers to change the font size and highlight sections. The main advantage of these formats is that Kindle devices and Amazon’s Kindle mobile app are the most popular ereaders. If a book is not available in Amazon’s Kindle store then it will not be easily accessible to many potential readers.
What is PDF?
PDF or Portable Document Format, is a type of electronic document where formatting is preserved in a fixed page layout and should be readable on any device and render in the same way. This isn’t always the case, however, and PDF is not the best way to distribute a finished ebook, as it it is open to piracy. Most ebook retailers use EPUB / MOBI to deliver content via ereaders.