E-book formats: which to choose?

EPUB (Electronic Publication) is currently the absolute market standard and the go-to format for both traditional publishers and self-publishers.

Key features:

• Reflowable text: The content dynamically adapts to the screen size and the reader’s personal settings.
• Highly device-friendly: Perfect for reading on smartphones, tablets, and e-ink readers (like PocketBook or Kobo).
• Full customisation: Allows users to easily adjust fonts, text size, line spacing, and margins.
• Multimedia support: Can handle rich media, including graphics, hyperlinks, and even video (in the EPUB3 standard).
• Interactive: Enables readers to highlight text and add personal notes.

 
In practice: EPUB is the most versatile format on the market, offering maximum reading comfort across almost all devices. It’s the perfect choice for novels, reportage, non-fiction, guidebooks, and educational materials. Its only real downside? It doesn’t replicate your printed page layout 1:1.

For years, MOBI was the default format for Amazon Kindle devices. Today, it’s gradually fading out. Amazon has largely replaced it with AZW3 and now seamlessly accepts EPUB files (handling the conversion internally). However, many readers still instinctively associate MOBI with “the Kindle format.”

Key features:

• A very lightweight and simple format.
• Fully compatible with older-generation Kindle devices.

 
In practice: While MOBI ensures compatibility with older Kindles and is easy to generate from an EPUB (using free tools like Calibre), it is now widely considered outdated. It struggles with advanced typography and multimedia, and its layout reproduction is inferior to EPUB. If you are creating an e-book for global distribution, an EPUB is usually all you need – Amazon will process it perfectly according to their latest guidelines.

While not a “true” e-book format in the traditional sense, PDF remains incredibly popular—especially for publications that need to look exactly like their printed counterparts.

Key features:

• Fixed layout: Fonts, sizing, and margins cannot be dynamically altered by the reader.
• Exact replication: Reproduces typography, graphics, and page design 1:1 with the print version.

 
In practice: PDFs are incredibly easy to export and remain the absolute best choice for content requiring precise formatting, such as textbooks, art albums, or books heavy on tables and diagrams. However, reading a PDF on a smartphone or a standard e-ink reader can be frustrating, as it requires constant zooming and scrolling. Furthermore, PDFs don’t allow for reading personalisation, and the files can be quite heavy if packed with high-resolution graphics. (We discuss this more in our article on Image File Formats).

Ideally, you should prepare at least two formats:

• EPUB (The Must-Have): The universally accepted format for the vast majority of online bookstores and e-readers.
• PDF (The Perfect Add-on): Highly useful if your book features complex typesetting or if you simply want to offer a digital replica of your print edition.

 
Pro tip: You can optionally prep a Kindle-specific format, but today, that doesn’t have to be a MOBI. Amazon happily accepts EPUBs and handles the conversion for you.

Adding an e-book version to your publishing strategy offers clear business advantages:

• Broader reach – especially for international readers.
• Lower distribution costs – zero shipping fees.
• No inventory risk – you never run out of stock, nor do you overprint.
• Expanded sales channels – access to global digital marketplaces.
• Faster time-to-market – instant publication.
• Bundle sales – the highly effective “Paperback + E-book” combo.

 
An e-book will never replace the tactile joy of paper, but it acts as a brilliant extension of your offer. In self-publishing, format diversity directly translates into more opportunities to capture new readers.

When choosing your e-book format, let the nature of your book and reader comfort be your guides. EPUB is the undisputed king for most publications, PDF steps in when layout is paramount, and MOBI serves mostly as a nod to users of older Kindles. Preparing a digital edition isn’t just a smart marketing move – it’s a proven strategy to boost sales and expand your audience.