Your Guide to the Different EBook Formats

| Updated on February 28, 2024
Different EBook Formats Explained

There are various factors to consider when creating and publishing eBooks. But the most crucial factor to consider is the format. Since eBooks are typically digital books, there are many formats you can publish them in. However, bear in mind that the viewing platform or eBook reader influences this decision since there are formats not supported on some platforms. 

We’ll discuss the different formats in this guide to help you choose which ones to use. However, if you’re here to see what you can do if you want to change the format of your eBook, know that it’s simple and easy with online converters like You can convert your eBook to another format with just a few clicks! 

Here are the most popular and widely used formats: 


This is the most widely used format for eBooks created by the International Digital Publishing Forum. EPUB or electronic publication is free, open-source, vendor-independent, and cost-efficient. This format can support or store images, texts, stylesheets, and metadata. Additionally, it explicitly supports color images, full videos, SVG graphics, and other interactive elements, unlike other formats. 

One of the best things about EPUB is that it can fit in almost any screen size without altering the screen formatting. It’s also viewed as reliable as MP3. All mainstream eBook readers and computer operating systems can read and open EPUB, except for Amazon Kindle. 

If you’re using Kindle, you’d need to convert EPUB into another file format, one that’s readable using Kindle. You can use for this purpose. Lastly, this format supports the DRM system, which can interest many authors. 

2. PDF 

A Portable Document Format is one of the most adopted and used formats in the digital publishing industry, not just for eBooks but also for other documents. Nowadays, it’s also one of the most used formats on the internet and the digital community. ISO:32000 certified PDF is also an open standard like EPUB. 

It’s easily readable on all mobile and computer devices. For those devices that can’t, downloading a PDF reader application is easy as there are many available online for any device, be it Windows, Android, iOs, etc. 

The only downside PDF has is that it’s a fixed layout type of format. It lacks native reflowing, which means it can’t adapt and fit its presentation according to the size of the screen, unlike other eBook formats. To circumnavigate this lack of reflowing, PDF can use tags in defining the structure of the document. 


This is also based on the Open eBook (OEB) format, like EPUB. Amazon bought MOBI from Mobipocket. Although Mobipocket is closed now, this format is still widely used, especially in Amazon Kindle. 

The main difference between EPUB and MOBI is that MOBI isn’t an open standard. This means it’s not publicly available. It can’t support sounds and videos in its files. Lastly, it can be opened to almost all readers except for Barnes and Noble Nook. 

4. AZW and AZW3

These are Amazon’s two proprietary eBook formats. AZW is the older one, while AZW3 is the most recent. Every time you download an eBook on Amazon, it will come in any of these two formats. However, typically, AZW3 is more advanced compared to AZW since it supports more styles, fonts, and layouts. 

It’s also similar to the MOBI format. But, unlike MOBI, these two formats can support sound and video. Additionally, they’re not widely supported by other readers since they’re proprietaries of Amazon. 

5. IBA

iBooks Author is proprietary to Apple Corporation. IBA is exclusive for Apple users of the iBooks Author app. This has many benefits, especially for Apple users. 

Technically, this is similar to EPUB, but it’s dependent on custom widget code in the Apple Books app to function, so it can’t be universally read on all eBook readers. Similarly, IBA supports images, sounds, videos, and other interactive digital elements. 

Here are some unpopular formats you might not even be aware of, but you can consider as well: 


These are extensions for the Broad Band eBook format and were Sony’s proprietary formats for its users’ use. Only LRS is open standard while the other two are still closed. However, all were abandoned by Sony for EPUB. 

2. FB2

This is developed in Russia and can store metadata within the file itself, which can come in handy in certain instances. Many readers and authors prefer this format because it’s easy to be converted into other formats. 


This is a popular eBook format, especially in the scientific community. Its compression mechanism is much better compared to PDF. Moreover, it can store more than 100 black and white scans in less than a megabyte. 

4. LIT

This was Microsoft’s proprietary ebook format. When DRM is enabled, LIT is only readable on the Microsoft reader app. However, in 2011, Microsoft discontinued this format, and readers vanished afterward. 

 5. RFT

Rich Text Format or RFT is compatible with almost any eBook reader. Unlike the TXT format, RFT can retain special characters and supports reflowing and text formatting.


There are many eBook formats you can publish or read in. Each has its own quirks and drawbacks that you need to compare to see which ones best fit you. You must be aware of all of these and know which formats are non-existent or aren’t supported anymore to avoid wasting effort.

Billy Willson


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