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

MDF file extension

Media Disc Image File

Disk Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files

THM file extension

Thumbnail Image File

Raster Image Files

ICO file extension

Icon File

System Files

KML file extension

Keyhole Markup Language File

GIS Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

PAGES file extension

Pages Document

Text Files

RSS file extension

Rich Site Summary

Web Files

PART file extension

Partially Downloaded File

Misc Files

M3U file extension

Media Playlist File

Audio Files

RPM file extension

Red Hat Package Manager File

Compressed Files

DAT file extension

Data File

Data Files

C file extension

C/C++ Source Code File

Developer Files

MDB file extension

Microsoft Access Database

Database Files