eBook Formats

There are many different ebook formats out there and they seem to give some confusion…what format can be read by what reader?  Below I’ve tried to summerize things a bit to help you out 🙂


The EPUB format is rapidly gaining popularity.

Published as: .epub

The format can be read at least by:

  • Kobo eReader
  •  Blackberry Playbook
  • Apple’s iBooks app running on iOS devices such as the iPhone, iPod Touch and iPad
  • Barnes and Noble Nook
  • Sony Reader
  • BeBook
  • Bookeen Cybook Gen3 (with firmware v. 2 and up)
  • Adobe Digital Editions
  • Lexcycle Stanza
  • BookGlutton
  • FBReader
  • Aldiko
  • Moon+ Reader and WordPlayer on Android
  • Freda on Windows Mobile and Windows Phone 7
  • the Mozilla Firefox add-on EPUBReader
  • Okular
  • Desktop reader software programs are currently implementing support for the format, such as dotReader, Mobipocket, uBook.
  • Adobe Digital Editions

The Amazon Kindle cannot read EPUB formats without them being converted* (more about that below) although there is constant speculation that Amazon will allow the Kindle to read this format soon.


Formerly Palm Digital Media/Peanut Press
Format: Palm Media
Published as: .pdb

eReader is a freeware program for viewing Palm Digital Media electronic books which use the .pdb format used originally by many Palm applications.  Versions are available for iPhone, PalmOS (not webOS), Android, Symbian, BlackBerry, Windows Mobile Pocket PC/Smartphone, desktop Windows, and Macintosh.

In 2009, Barnes & Noble announcedthat the eReader format will be the method they will use to deliver e-books.  The Nook Reader supports the eReader format but be warned, the Nook Color doesn’t! (nothing like making things complicated is there!).


iBook (Apple)

Format: iBook
Published as: .ibooks

The .ibooks format is created with the free iBooks Author ebook layout software from Apple Inc. It’s based on the EPUB format, but you can’t expect Apple to just leave it alone so they’ve added in their own bits and pieces  which effectively makes it incompatible with any of the epub readers (which is probably what Apple were after doing anyway!).  If you are planning on creating a book in the iBook format, bear in mind that Apple End-User Licensing Agreement (EULA) states

“If you want to charge a fee for a work that includes files in the .ibooks format generated using iBooks Author, you may only sell or distribute such work through Apple”

Which means that you can only sell the book through iTunes and you have to pay Apple a huge royalty 🙁


KF8 (Amazon Kindle)

Format: Kindle
Published as: .azw; .kf8

The Kindle Fire reader uses the .kf8 file format which has a subset of HTML5 and CSS3 features, with some additional nonstandard features just for the Kindle Fire.  The new data is stored within a container which can also be used to store a MOBI content document which allows some compatibility with older devices.

The .azw format is what is used by the other members of the Kindle family and is based on the Mobipocket standard.  Because eBooks bought on the Kindle are delivered over its wireless system, Whispernet, you don’t see the AZW files during the download process (although you can get to the files if you plug your Kindle into a computer). The Kindle format is now available on a variety of platforms, such as through the Kindle app for the iPad.


* How to go about converting ebook formats from one to another

There’s a free program called Calibre that can be used to take in an ebook in one format and put it out into a different format as required.  This is really useful as lots of ebook sites that offer free books have them in epub format and I want to be able to read them on my Kindle.  All I do is ‘suck’ them into Calibre, convert them to .azw, spit them out, attach my Kindle to my computer and drag my book to my eReader…simple!


Google offer over a million free e-books in EPUB format but that isn’t an awful lot of use if you have a Kindle… so,


Open and run Calibre.  On the LEFT will be your choices for set-up when you’re converting a document.  Hovering over anything will usually bring a help tip.

Accepting defaults is fine.  The ability to change the “meta information” is nice – so you can have names and authors as you like them.  If there is no Table of Contents you can ‘force’ Calibre to create one.

At the top are choices to “Edit meta information: as well as “Convert E-books.” Follow the instructions, and then press the ‘OK’ button and the conversion will take a few minutes.  I’ve converted loads and moved them to my Kindle Keyboard and they all look great and have the option to adjust font size and spacing, just like normal Kindle books.

So, yes, those million+ free Google books are fully useable on the Kindle – it just needs this added step, but it’s also great to be able to customize so much of the layout if you want.  Play with the software a bit.