EPUB, mobi, PDF—Understanding digital book formats

18.08.2016 |

Episode #5 of the course How to self-publish a book by Emmanuel Nataf


If you’ve hired a designer to work on a book’s interior, you won’t really need to worry about formats—they will provide you with all the files you need to distribute your book. But if you’re working by yourself—or you simply want to know how the sausage is made—this lesson will show you the basic differences between the most popular formats for self-published books.

Depending on your distribution plans, there are three formats you need to know about—EPUB and mobi files for ebooks, and print-ready PDFs (guess why you might need those).



This is the most common format for ebooks. It’s a standard based on HTML and it allows for “reflowable text,” meaning that the book can easily optimize itself to any device, whether it’s on an e-reader or an iPhone.

All major retailers, apart from Amazon, use it on their platforms. If you want to upload to any other ebook retail platform—through Kobo Writing Life or Nook Press, for example—or use an “aggregator” like Smashwords or Draft2Digital, you will need to have an EPUB file.



When you purchase an ebook on the Kindle store, it arrives on your device in the mobi format: a standard owned and used by Amazon. At its heart, it’s not that different from an EPUB file, with the exception that mobi files sold by Kindle are “locked” to devices registered to your account.

Kindle Direct Publishing automatically converts all books to mobi before displaying them on their store. The best way to ensure your formatting doesn’t get mangled in that conversion is to upload using the EPUB format.


How to get what you need

If you don’t want to deal with all this by yourself, there are paid services that will format and typeset your book. But what if there was an easy way to get your book ready for distribution without paying a single penny? Well, now that you mention it…

Remember the Reedsy Book Editor? We could go on and on about why it’s so awesome, but the most important thing is that it doesn’t need an “instruction manual”. You can just write your book and forget about the formatting. The Editor is fully compliant with all major ebook and print-on-demand retailer requirements, so you don’t have to think about each store on a case-by-case basis. And of course, the Editor is completely free.

You’re finally ready to share your book with the world, come back tomorrow to find out how!


Recommended book:

“Secrets to Ebook Publishing Success” by Mark Coker


Share with friends