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

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

M3U file extension

Media Playlist File

Audio Files

CSR file extension

Certificate Signing Request File

Web Files

WMA file extension

Windows Media Audio File

Audio Files

ASP file extension

Active Server Page

Web Files

CER file extension

Internet Security Certificate

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

PAGES file extension

Pages Document

Text Files

TIF file extension

Tagged Image File

Raster Image Files

DRV file extension

Device Driver

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

HTM file extension

Hypertext Markup Language File

Web Files

MPA file extension

MPEG-2 Audio File

Audio Files

ASPX file extension

Active Server Page Extended File

Web Files

SLN file extension

Visual Studio Solution File

Developer Files