What is a .MOBI file?

.MOBI is a file extension created for eBooks. .MOBI files have mostly been used for devices such as the Amazon Kindle or other mobile devices with low bandwidth. Aside from eBook data, a MOBI file may also contain DRM (Digital Rights Management) copyright protection - which can be used to prevent unauthorised duplication and distribution.

What does .MOBI stand for?

MOBI is an abbreviation of ‘Mobipocket’, which is a software package designed for publishing and reading eBooks.

It is therefore not an acronym or initialisation, unlike many other file type extensions.

History of the .MOBI file.

A French company developed the MOBI format in 2000, though its original extension was actually .PRC.

After Amazon bought Mobipocket in 2005, they released the .MOBI format as a standard for their Kindle devices just a couple of years later. MOBI 7, the most recent version of MOBI, is also known as KF7 (standing for Kindle Fire version 7). Sometimes these files have an .AZW extension, due to the fact that they use Amazon’s own DRM system.

In 2011, however, Amazon discontinued support for the MOBI format and the .AZW3 became the preferred file extension for the Amazon Kindle devices and the Amazon’s marketplace.

In August 2022, Amazon officially retired the MOBI format and replaced it with EPUB, which is now the universal format for eBook.

Today, MOBI files can still be opened using a compatible MOBI reader or by converting them to a more up to date format.

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What are .MOBI files used for?

Publishing eBooks.

Prior to August 2022, many authors used MOBI files to publish their eBooks. They were also able to embed DRM copyright protection within these files, to prevent unauthorised viewing or copying of their work.

Accessing and storing eBooks.

Although the format has been discontinued, if you have any MOBI and AZW files in your library, you can still open them using a compatible programme.

Discover more document file types and types of eBook file.

Pros and cons of .MOBI files.


  • Reflowable format. You can make the fonts bigger or smaller and the text will automatically rearrange on the page.
  • Features beyond just reading. You can add bookmarks, notes or corrections throughout your eBook. On Kindle applications, any bookmarks or annotations used to be stored in a separate file with the .MBP extension or the .SMBP suffix if the file was encrypted. MOBI files also support JavaScript and frames.
  • Accessible by mobile devices with low bandwidth. You can read eBooks saved as MOBI files on mobile phones, eReaders and tablets.


  • Amazon’s proprietary format. Specially designed for Amazon’s Kindle devices, this means that other devices may need additional software or plugins to access MOBI files.
  • Discontinued in August 2022. You cannot easily download or distribute MOBI files any more - and they are an effectively a less relevant format.
  • Require conversion to EPUB. If you still have MOBI files on your device, they’ll need to be converted to the EPUB format to access all the features available.

How to open a .MOBI file.

To open a .MOBI file, you need a .MOBI reader. The Amazon Kindle App is the most popular option to access MOBI eBooks, as it’s supported on Windows, macOS and smartphones. Other free software that can open .Mobi files include Mobipocket Reader, Calibre, Stanza. You can even read MOBI eBooks on the browser, by install the Chrome extension ‘MOBI Reader’.

How to create and edit a .MOBI file.

You cannot create and edit MOBI files any more. Before the MOBI format was discontinued, authors were able to create and edit MOBI files in various eBook software like Calibre and Kindle Create.

Today, if you want to edit an eBook that has been created in the MOBI format, you will first need to convert it.

Convert a MOBI file to PDF.

Many file types, including eBook files, can be converted to PDF using Adobe’s free online conversion tool.

  • Simply drag and drop your file into place or upload it.
  • When the conversion has been completed, save your new PDF to your device or share it.

You can also then sign and edit your PDF if desired.

Learn more about similar file types to MOBI.


Discover more about the open standard format for eBooks, developed by the International Digital Publishing Forum (IDPF).


Check out this basic plain text file type that can be opened and edited in any text-editing software.


Find out more about one of the most popular word processing file types with our guide.


Discover one of the most reliable and widespread document file formats and everything you can do with it.

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What is the difference between EPUB and MOBI?

The main difference between these two eBook file types is that MOBI was Amazon’s proprietary eBook format prior to 2011 and was predominantly used for Kindle devices, while EPUB is more universal as it’s supported across all platforms. Amazon discontinued the MOBI format in 2022 and EPUB has now become an open standard for eBooks in general.

Does Adobe read MOBI?

Adobe Digital Editions can read Mobi files. However, you may need to convert the Mobi file to a compatible format such as EPUB or PDF using a third-party conversion tool before importing it into Adobe Digital Editions

Is MOBI obsolete?

As MOBI files have been discontinued, they are certainly outdated compared to the EPUB format. These days, using the MOBI format may limit access to certain useful eBook features - so it is advised that you convert them if possible. That said, certain readers and programmes will still allow you to view MOBI files if you wish.

How do I convert a MOBI file to EPUB?

As EPUB is the standard eBook format used among publishers, it’s advisable to convert any old MOBI files you may have to EPUB so you can take advantage of all features. To do this, you can download Calibre for free or use an online file convertor.