File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

PCT file extension

Picture File

Layout Files

3GP file extension

3GPP Multimedia File

Video Files

CFM file extension

ColdFusion Markup File

Web Files

WAV file extension

WAVE Audio File

Audio Files

MPG file extension

MPEG Video File

Video Files

RPM file extension

Red Hat Package Manager File

Compressed Files

C file extension

C/C++ Source Code File

Developer Files

CUR file extension

Windows Cursor

System Files

7Z file extension

7-Zip Compressed File

Compressed Files

ASF file extension

Advanced Systems Format File

Video Files

CBR file extension

Comic Book RAR Archive

Compressed Files

PIF file extension

Program Information File

Executable Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

DBF file extension

Database File

Database Files

KEY file extension

Keynote Presentation

Data Files