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

GPX file extension

GPS Exchange File

GIS Files

PDF file extension

Portable Document Format File

Layout Files

TIF file extension

Tagged Image File

Raster Image Files

MAX file extension

3ds Max Scene File

3D Image Files

CSR file extension

Certificate Signing Request File

Web Files

XML file extension

XML File

Data Files

KML file extension

Keyhole Markup Language File

GIS Files

CFG file extension

Configuration File

Settings Files

M3U file extension

Media Playlist File

Audio Files

NES file extension

Nintendo (NES) ROM File

Game Files

CAB file extension

Windows Cabinet File

System Files

RA file extension

Real Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

IFF file extension

Interchange File Format

Audio Files