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

AVI file extension

Audio Video Interleave File

Video Files

CSV file extension

Comma Separated Values File

Data Files

DEM file extension

Video Game Demo File

Game Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

HTM file extension

Hypertext Markup Language File

Web Files

ICO file extension

Icon File

System Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PCT file extension

Picture File

Layout Files

RM file extension

Real Media File

Video Files

SH file extension

Bash Shell Script

Developer Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TXT file extension

Plain Text File

Text Files

UUE file extension

Uuencoded File

Encoded Files

ZIPX file extension

Extended Zip File

Compressed Files