EPUB Vs Mobi: What Is the Difference?

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  • February 19, 2024
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  • 9 min read


EPUB and MOBI are two of the most popular ebook formats used by e-readers and ebook readers today. Both formats have existed for over a decade and have evolved to support advanced ebook features.

This article will examine EPUB vs. Mobi regarding features, compatibility, popularity, advantages, and disadvantages to help you determine which format best caters to your requirements as a reader or even in the context of professional book writing.

What is EPUB?

EPUB (short for electronic publication) is an open standard digital book format developed by the International Digital Publishing Forum (IDPF). Unlike proprietary ebook formats like Amazon’s .mobi, EPUB is designed to be supported across different software and hardware platforms. A comprehensive understanding of the EPUB format is essential when developing a book editing outline to ensure compatibility and readability for your target audience.

Some key things to know about the EPUB format:

  • EPUB files use the .epub file extension. The .epub extension is a container for HTML, CSS, images, and other files to display the ebook content.
  • EPUB builds on existing web standards like HTML, CSS, and XML to create reflowable content that adapts to different screen sizes. This makes EPUB ideal for reading on mobile devices.
  • The EPUB format supports text, images, multimedia, metadata, and interactivity/scripting. EPUB3, the latest version, supports math formulas, audio, video, and fixed layouts.
  • EPUB files can be read on various devices, apps, and programs. Any app or device that supports EPUB can open and render .epub files.
  • EPUB is maintained and developed by the IDPF, including major companies like Google, Amazon, and Apple. This open standard ensures EPUB remains universally supported.

What is MOBI?

MOBI is a proprietary ebook format created by Amazon. Specifically, it stands for Mobipocket, an ebook store and reading platform acquired by Amazon in 2005.

The MOBI format was originally based on the Open eBook standard using XHTML and CSS styling. Created by Mobipocket around 2000 and later acquired by Amazon in 2005, MOBI has evolved into a significant element in the self-publishing Amazon ecosystem.

Some key things to know about the MOBI format:

  • Developed by Mobipocket around 2000, acquired by Amazon in 2005
  • Proprietary format owned by Amazon
  • Primary ebook format used by Amazon Kindle devices and reading apps
  • Uses a .mobi file extension
  • Based on and similar to the Open eBook standard
  • Supports DRM copy protection
  • Smaller file size compared to EPUB
  • Limited styling and formatting options compared to EPUB

Key Differences Between EPUB and Mobi:

Here are some of the key differences between EPUB vs. Mobi so that when you are choosing between these two, you can make an informed decision.

EPUB vs MOBI Features

When it comes to features, EPUB vs. Mobi differ in a few key ways:

· Text

EPUB supports reflowable text, which adjusts the text based on the screen size. This makes it great for reading on different devices with different displays.

MOBI does not have reflowable text. The text formatting is fixed, so the reading experience may not be ideal on all devices.

· Images

EPUB supports both JPEG and PNG image formats. Images will resize automatically on different screens.

MOBI only supports older JPEG and GIF formats. Images are fixed and won’t resize.

· Multimedia

EPUB supports embedded multimedia like audio and video clips, enhancing the reading experience.

MOBI does not support embedded multimedia at all, so this is why audio and video are not options.

EPUB vs MOBI Compatibility

Regarding compatibility, EPUB vs. Mobi significantly differs in device and app support. This insight is especially useful for those utilizing manuscript editing services who might want to consider which format best suits their target readership.

MOBI is the proprietary format developed by Amazon specifically for Kindle devices and apps. As a result, MOBI has seamless integration and native support on all Kindle e-readers and Kindle reading apps across platforms like iOS, Android, Windows, and Mac. MOBI files sync easily across Kindle devices registered to the same Amazon account.

EPUB has wider device and app support beyond Amazon ecosystems. EPUB is the industry standard format supported by most other e-readers, e-reading apps, and online libraries.

Popular EPUB-compatible devices include:

  • Kobo
  • Nook
  • Sony Reader
  • Google Play Books app
  • Apple Books app
  • Adobe Digital Editions, etc.

EPUB also works across operating systems like iOS, Android, Windows, and Mac.

However, EPUB compatibility can be inconsistent across apps and devices. Some earlier-generation e-ink readers may lack full EPUB 3 support. E-reading apps sometimes use slightly different EPUB rendering engines, which can lead to formatting issues. Compared to MOBI on Kindle, EPUB tends to be more prone to syncing and formatting inconsistencies across devices and apps. But EPUB still enjoys relatively broad compatibility given its support as the standard ebook format.

MOBI offers seamless integration but only works within the Kindle ecosystem, while EPUB provides wider yet imperfect compatibility across devices and apps. Neither format fully dominates in terms of compatibility. When choosing between EPUB and MOBI, you must consider which devices or apps you plan to use for reading the ebook.

EPUB vs. MOBI Popularity

EPUB has become the most widely adopted ebook format, while MOBI has declined in popularity recently. Most estimates say EPUB makes up over 60% of the ebook market. Its share continues to grow as more ebook stores, libraries and publishers move to support the EPUB format.

MOBI was once very popular because Amazon’s Kindle devices only initially supported the MOBI format. However, Kindle devices began supporting EPUB in the late 2010s. Since then, MOBI’s market share has declined to around 15-20% as of 2022.

Major ebook stores like Google Play, iBooks, Kobo, Nook, and others use EPUB as their principal format. Kindle remains the only major store still using MOBI as its default format, though it now supports EPUB as well, a vital point to consider for authors planning to sell ebooks on Amazon.

Public libraries and academic institutions overwhelmingly favor EPUB for lending out ebooks. Its support for accessibility features like read-aloud and font adjustment makes it preferable for public use.

Most ebook publishers now create and distribute books in EPUB format. Few exclusive MOBI releases are published outside Amazon’s Kindle Direct Publishing platform.

Unless Amazon makes Kindle exclusivity mandatory, EPUB’s lead over MOBI will likely continue growing.

EPUB vs. MOBI Pros and Cons

In book publishing, selecting the right ebook format is critical. Here’s an overview of the main pros and cons of EPUB and MOBI formats, which may influence your decision at various stages of publishing:


  • Supported by most ebook readers – EPUB has wider device support and can be read on most ebook readers except Amazon Kindle.
  • Reflowable content – EPUB reflows text to fit different screen sizes automatically. This makes it good for reading on a variety of devices.
  • Accessible format – EPUB has strong accessibility features to support readers with print disabilities.
  • Multimedia support – EPUB supports embedding multimedia like audio, video and interactive elements.
  • Digital rights management – EPUB supports DRM to control access and copying of ebooks.


  • Not supported on Amazon Kindle – Amazon Kindle devices do not support EPUB format by default. EPUB books have to be converted to Kindle format for Amazon devices.
  • Larger file sizes – EPUB files are typically larger compared to MOBI files. This takes up more storage space.
  • Limited layout control – EPUB reflows content and does not allow extensive control over fixed layouts.


  • Supported on Kindle – MOBI is the proprietary format for Amazon Kindle and has native support.
  • Smaller file size – MOBI files are much smaller than EPUB, taking up less storage space.
  • Preserves complex layouts – MOBI can handle more complex and fixed layouts like images, tables, etc.
  • Digital rights management – MOBI also supports DRM like EPUB.


  • Limited device support – MOBI is mainly for Amazon Kindle devices. Other ebook readers have limited support for MOBI.
  • No multimedia support – MOBI does not support embedding multimedia or interactive content.
  • Less accessible format – MOBI has fewer accessibility features compared to EPUB.

The Future of EPUB and MOBI

Both EPUB vs. Mobi BI are popular ebook formats that will likely continue to exist. However, there are some predictions on which format may become more dominant.

EPUB has the advantage of being an open standard supported by many devices and reading apps. Its flexibility and support for advanced layouts make it well-suited for complex and illustrated books. This strength of EPUB, as recognized by many publishers and demonstrated in the services offered by Ghost Writing Founder, could gradually establish it as the go-to ebook format.

However, Amazon’s proprietary MOBI format dominates the ebook market share currently. With Kindle’s popularity, Amazon has leverage to continue pushing MOBI as the main format. However, Kindle devices and apps have EPUB support as well.

Over time, EPUB vs. Mobi may gain more ubiquity across platforms and overtake MOBI in usage. But MOBI will likely continue to persist, given Amazon’s market position. Publishers may need to provide books in both formats to reach the widest audience.

The rise of web-based and browser-based reading platforms could also favor EPUB’s advantages and increase its adoption over MOBI. But native apps and e-readers may ensure MOBI remains relevant.

EPUB and MOBI may eventually converge into a unified ebook standard that combines their best attributes. But shortly, both formats will likely continue co-existing as popular ebook publishing options. The competition between an open standard like EPUB and a proprietary standard like MOBI will likely continue to shape the ebook landscape.


Overall, both formats will likely continue evolving and co-existing. EPUB vs. Mobi will remain the dominant open standard, while MOBI retains dominance in the Amazon Kindle ecosystem.

Most readers’ optimal format will depend on their preferred devices and reading platforms. The most important factor is accessing and enjoying your ebook content on whichever device or app you choose.

The most important factor in choosing between EPUB vs. Mobi is simply accessing and enjoying your ebook content on whichever device or app you choose.

As technology advances and reader preferences shift, flexibility and compatibility will remain paramount in ensuring an enjoyable reading experience. Adaptability to changing trends will be key for both formats, EPUB vs. Mobi, to thrive in the changing landscape of digital publishing.

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