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

CUE file extension

Cue Sheet File

Disk Image Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

SDF file extension

Standard Data File

Data Files

PNG file extension

Portable Network Graphic

Raster Image Files

3G2 file extension

3GPP2 Multimedia File

Video Files

ASPX file extension

Active Server Page Extended File

Web Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

M4A file extension

MPEG-4 Audio File

Audio Files

INDD file extension

Adobe InDesign Document

Layout Files

VB file extension

VBScript File

Executable Files

PL file extension

Perl Script

Developer Files

PRF file extension

Outlook Profile File

Settings Files

CRX file extension

Chrome Extension

Plugin Files

DOC# file extension

Microsoft Word Document

Text Files