.MOBI File Extension

Mobipocket eBook

Developer Amazon
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What is a MOBI file?

A MOBI file is a digital book (eBook) saved in the proprietary MOBI format. It contains binary data that makes up an eBook (a book, magazine, scientific publication, etc.) and may incorporate DRM copyright protection to prevent copying or unauthorized viewing. Various eReaders, tablets, and software, including Calibre and Geometer Plus FBReader, support MOBI files.

More Information

Screenshot of a .mobi file in Calibre 3
MOBI file open in Calibre 3

The Mobipocket Reader initially used the MOBI format, then other readers eventually supported it. The format supports various features including notes, corrections, and bookmarks.

Amazon acquired MOBI in 2005 and used it exclusively for its eReaders. It then replaced MOBI with the Kindle Format 8 (KF8), which was saved and distributed as .mobi or .azw3 (.AZW3) files. However, Amazon discontinued the development of the AZW3 and MOBI formats in 2022 in favor of the industry standard.EPUB format.

How to open a MOBI file

You can open a MOBI file with various apps, including Calibre and Geometer Plus FBReader. For example, to open a MOBI file with Calibre, select File → Open.

How to convert a MOBI file

Calibre can convert MOBI files to various file types, including the following formats:

  • .AZW3 - Amazon KF8 eBook
  • .EPUB - Open eBook
  • .FB2 - FictionBook 2.0 File
  • .LIT - eBook File
  • .LRF - Sony Portable Reader File
  • .PDF - Portable Document Format
  • .DOCX - Microsoft Word Document
  • .RTF - Rich Text Format
  • .TXT - Plain Text
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Programs that open MOBI files

Verified by FileInfo.com

The FileInfo.com team has independently researched the Mobipocket eBook file format and Mac, Windows, Linux, and Android apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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