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

APK file extension

Android Package File

Executable Files

WMA file extension

Windows Media Audio File

Audio Files

CSS file extension

Cascading Style Sheet

Web Files

DDS file extension

DirectDraw Surface

Raster Image Files

ASX file extension

Microsoft ASF Redirector File

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

PPT file extension

PowerPoint Presentation

Data Files

FNT file extension

Windows Font File

Font Files

PHP file extension

PHP Source Code File

Web Files

TARGZ file extension

Compressed Tarball File

Compressed Files

PDB file extension

Program Database

Database Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

7Z file extension

7-Zip Compressed File

Compressed Files