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

CS file extension

Visual C# Source Code File

Developer Files

XCODEPROJ file extension

Xcode Project

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files

CSR file extension

Certificate Signing Request File

Web Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

PPS file extension

PowerPoint Slide Show

Data Files

SAV file extension

Saved Game

Game Files

TIFF file extension

Tagged Image File Format

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

TXT file extension

Plain Text File

Text Files

DOC# file extension

Microsoft Word Document

Text Files

DDS file extension

DirectDraw Surface

Raster Image Files

KMZ file extension

Google Earth Placemark File

GIS Files

CPP file extension

C++ Source Code File

Developer Files