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

C file extension

C/C++ Source Code File

Developer Files

COM file extension

DOS Command File

Executable Files

DDS file extension

DirectDraw Surface

Raster Image Files

DMP file extension

Windows Memory Dump

System Files

ICO file extension

Icon File

System Files

PPS file extension

PowerPoint Slide Show

Data Files

PS file extension

PostScript File

Vector Image Files

SITX file extension

StuffIt X Archive

Compressed Files

SLN file extension

Visual Studio Solution File

Developer Files

TARGZ file extension

Compressed Tarball File

Compressed Files

WMA file extension

Windows Media Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files

3DS file extension

3D Studio Scene

3D Image Files