A cer file extension is related to the Internet security certificate files. These certificate files are used to secure internet transactions etc.

There are 4 other file types using
the CER file extension!

empty icon.cer - Lahey Fortran compilation error message

empty icon.cer - Cerius2 data

empty icon.cer - Creatacard certificate project

empty icon.cer - Sierra Print Artist certificate

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CER file extension - Internet security certificate

What is cer file? How to open cer files?

The cer file extension is associated with the Internet Security Certificate files. Security certificates are used to Secure Internet server, web site transactions, logins, webmail and connections. They can use SSL encryption.

MIME types:


The default software associated to open cer file:

Microsoft Edge icon

Microsoft Corporation logoMicrosoft Edge  Microsoft Windows software

Company or developer:
Microsoft Corporation

Microsoft Edge is web browser introduced in Microsoft Windows 10 operating system. It's fast and built for modern web applications and presentations. It allows users to simple share, reading and discover the Internet.

Microsoft Internet Explorer icon

Microsoft Corporation logoMicrosoft Internet Explorer  Microsoft Windows software

Company or developer:
Microsoft Corporation

Microsoft Internet Explorer was traditionally used as a default web browser that comes as part of the Microsoft Windows operating system. The last version was Internet Explorer 11.

Internet Explorer was retired on June 15, 2022, and replaced by a new Microsoft Edge browser.

Microsoft Windows 10 also contains Internet Explorer, but as default browser is used Microsoft Edge. It was removed in newer Windows OS versions.

Safari icon

Apple, Inc. logoSafari  Apple macOS / Mac OS X software

Company or developer:
Apple, Inc.

Safari is the default web browser integrated to Apple Mac OS X since version 10.3 "Panther". It is also used in iOS devices like iPads and IPhones.

Help how to open:

Use compatible tools to work with *.cer files.

How to convert:

As far as we know, this .cer file type can't be converted to any other file format. This is usually the case of system, configuration, temporary, or data files containing data exclusive to only one software and used for its own purposes. Also some proprietary or closed file formats cannot be converted to more common file types in order to protect the intellectual property of the developer, which is for example the case of some DRM-protected multimedia files.

List of recommended software applications associated to the .cer file extension

Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open cer file, edit cer file, convert cer file, view cer file, play cer file etc. (if exist software for corresponding action in File-Extensions.org's database).

Unspecified and all other actions for computer programs working with cer file - Internet security certificate

Click on the software link(s) for more information. Suggested software applications use cer file type for internal purposes and/or also by different way than common edit or open cer file actions.

Microsoft Windows:

Main software associated with cer file by default:
Microsoft Edge small icon Microsoft Edge
Microsoft Internet Explorer small icon Microsoft Internet Explorer
Other suggested software:
Opera browser small icon Opera browser
Firefox small icon Firefox
Google Chrome small icon Google Chrome
Chromium small icon Chromium
SeaMonkey small icon SeaMonkey
Safari for Microsoft Windows small icon Safari for Microsoft Windows

Apple macOS / Mac OS X:

Main software associated with cer file by default:
Safari small icon Safari
Other suggested software:
Opera browser for Mac small icon Opera browser for Mac
Google Chrome for Mac small icon Google Chrome for Mac
Firefox for Mac small icon Firefox for Mac
Chromium for Mac small icon Chromium for Mac

Apple iOS (iPhone, iPad, iPod Touch devices):

Other operating systems or devices:

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