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

CER file extension

Internet Security Certificate

Web Files

CSR file extension

Certificate Signing Request File

Web Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

DRV file extension

Device Driver

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

LNK file extension

Windows File Shortcut

System Files

LUA file extension

Lua Source File

Developer Files

MPA file extension

MPEG-2 Audio File

Audio Files

MPG file extension

MPEG Video File

Video Files

PL file extension

Perl Script

Developer Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SYS file extension

Windows System File

System Files

VB file extension

VBScript File

Executable Files

WPD file extension

WordPerfect Document

Text Files

YUV file extension

YUV Encoded Image File

Raster Image Files