1. Technology
You can opt-out at any time. Please refer to our privacy policy for contact information.

What is a MOBI File?


Question: What is a MOBI File?

Did you find a MOBI file on your computer and wonder what program should open it? Maybe someone emailed you a MOBI file but you're not sure how to use it. Perhaps you tried to open the MOBI file but Windows told you that it could not open it.

Before you can open a MOBI file (assuming it's even a file format that's intended to be viewed or edited), you'll need to determine what kind of file the .MOBI file extension refers to.

Answer: A file with the MOBI file extension is a Mobipocket eBook file.

Other types of files may also use the MOBI file extension. If you know of any additional file formats that use the .MOBI extension, please let me know so I can update this information.

How To Open a MOBI File

The easiest way to open a MOBI file is to double-click on it and let your PC decide which default application should open the file. If no program opens the MOBI file then you probably don't have an application installed that can view and/or edit MOBI files.

Warning: Take great care when opening executable file formats received via email or downloaded from websites you're not familiar with. See my List of Executable File Extensions for a listing of file extensions to avoid and why.

MOBI files can be read by Mobipocket Reader and created by Mobipocket Creator, both free programs by Mobipocket. Three other notable free programs that can open MOBI files are Calibre, Stanza Desktop, and Sumatra PDF.

MOBI files can also be read by popular eBook readers like the Amazon Kindle and many smartphones that support the format.

Additionally, many eBook readers, again, like the popular Kindle device, also have desktop software, mobile apps, and browser tools that allow the reading of MOBI files.

If you know of any other programs that open or edit MOBI files, please send me a quick email and let me know so I can update this page.

Tip: Use Notepad or another text editor to open the MOBI file. Many files are text-only files meaning no matter the file extension, a text editor may be able to properly display the file's contents. I don't think this is the case with the MOBI format but you might be able to view file header or other information about the eBook by opening it in Notepad.

If you find that an application on your PC does try to open the MOBI file but it's the wrong application or if you would rather have another installed program open MOBI files, see my How To Change the Default Program for a Specific File Extension guide for making that change in Windows.

How To Convert a MOBI File

There are three main ways to attempt to convert a MOBI file to another file type:

  • Open the MOBI file in its default program and choose to save the open file as another file format.
  • Download and install Calibre and use it to convert to and from the MOBI eBook format.
  • Use another File Conversion Online Service or Software Program to convert the MOBI file to another file format.

The first option involving opening the MOBI file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens MOBI files, Calibre or another third-party file conversion tool could be very useful.

Important: You cannot usually change a file extension (like the MOBI file extension) to one that your computer recognizes and expect the newly renamed file to be usable. An actual file format conversion using one of the methods described above must take place in most cases.

Still Having Problems Opening or Using a MOBI File?

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the MOBI file and I'll see what I can do to help.

©2014 About.com. All rights reserved.