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

ASPX file extension

Active Server Page Extended File

Web Files

CRX file extension

Chrome Extension

Plugin Files

DEM file extension

Video Game Demo File

Game Files

DOC file extension

Microsoft Word Document

Text Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IFF file extension

Interchange File Format

Audio Files

MDF file extension

Media Disc Image File

Disk Image Files

SDF file extension

Standard Data File

Data Files

SH file extension

Bash Shell Script

Developer Files

SQL file extension

Structured Query Language Data File

Database Files

TARGZ file extension

Compressed Tarball File

Compressed Files

WMV file extension

Windows Media Video File

Video Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files