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

AIF file extension

Audio Interchange File Format

Audio Files

CPL file extension

Windows Control Panel Item

System Files

LNK file extension

Windows File Shortcut

System Files

M4A file extension

MPEG-4 Audio File

Audio Files

NES file extension

Nintendo (NES) ROM File

Game Files

ODT file extension

OpenDocument Text Document

Text Files

PS file extension

PostScript File

Vector Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SH file extension

Bash Shell Script

Developer Files

SRT file extension

SubRip Subtitle File

Video Files

THM file extension

Thumbnail Image File

Raster Image Files

TXT file extension

Plain Text File

Text Files

WMA file extension

Windows Media Audio File

Audio Files

WMV file extension

Windows Media Video File

Video Files

3GP file extension

3GPP Multimedia File

Video Files