All electronic books—in fact, all digital media—are stored in files using a series of conventions known as a format. The specific format (the way the information is stored in the file) lets a device, such as a computer or an ereader, make sense of the contents of the file.
Common examples of electronic book formats include MOBI/AZW (used in the Amazon Kindle), EPUB (used by many ereaders including the Barnes & Noble NOOK and the Apple iPad), and Adobe Portable Document Format (PDF).
You, as an author or publisher, need to understand the landscape of electronic formats because most ereaders support only a subset of the available ebook formats, and some readers support certain formats better than others.
Your choice of format affects the specific ereaders and ebook markets that you target with your material. Perhaps more importantly, it will also affect the tools and procedures you use to create your ebooks (not all tools support all formats).
This article provides a brief overview of the most popular ebook formats available in the market today (subsequent articles in this series focus on each of the formats). When reading these articles, don’t worry too much about remembering specific technical details. Instead, think about the kinds of books you are hoping to publish and keep a mental score of which formats seem most suitable for your material.
Ebook Formats at a Glance
|
Format |
Summary |
|
Amazon Kindle (MOBI/AZW) |
A popular and easy-to-learn format available on the most popular ereaders, namely Amazon Kindles. |
|
Amazon Kindle Format 8 (KF8) |
A new format, announced with the Kindle Fire tablet, featuring the latest web standards including HTML5 and CSS3. |
|
EPUB |
An industry standard format supported by multiple ereaders and vendors, including Apple, Barnes & Noble, and Kobo, among others. |
|
EPUB3 |
A recently-introduced industry standard format also incorporating the latest web standards including HTML5 and CSS3. |
|
Portable Document Format (PDF) |
An industry standard electronic document format offering advanced typography and layout, but not ideal for ereaders with smaller screens. |
Though currently not as popular for mainstream ebooks, three additional formats are worthy of consideration: mobile applications (for iPad or Android devices), Kurzweil Blio, and HTML5. The following table provides a summary of these additional ebook formats:
|
Format |
Summary |
|
Mobile applications |
Incredibly flexible, limited only by your imagination, though potentially costly and complex to develop. |
|
Kurzweil Blio (XPS) |
Offers some of the best features of print books, including advanced typography and layout, but currently not widely supported. |
|
HTML5 |
Though available in both Kindle Format 8 and EPUB3, HTML5 offers the opportunity to add multimedia and interactivity directly as an alternative to more complex and costly mobile applications. |
“PrintingPress” by WikiRigaou – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
