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

7Z file extension

7-Zip Compressed File

Compressed Files

DRV file extension

Device Driver

System Files

GPX file extension

GPS Exchange File

GIS Files

SLN file extension

Visual Studio Solution File

Developer Files

ZIP file extension

Zipped File

Compressed Files

CUE file extension

Cue Sheet File

Disk Image Files

JSP file extension

Java Server Page

Web Files

THM file extension

Thumbnail Image File

Raster Image Files

XML file extension

XML File

Data Files

SYS file extension

Windows System File

System Files

TTF file extension

TrueType Font

Font Files

M3U file extension

Media Playlist File

Audio Files

ICO file extension

Icon File

System Files

CAB file extension

Windows Cabinet File

System Files

RTF file extension

Rich Text Format File

Text Files