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

DRV file extension

Device Driver

System Files

GAM file extension

Saved Game File

Game Files

LOG file extension

Log File

Text Files

M4V file extension

iTunes Video File

Video Files

PART file extension

Partially Downloaded File

Misc Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

SWF file extension

Shockwave Flash Movie

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TTF file extension

TrueType Font

Font Files

WPD file extension

WordPerfect Document

Text Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

3GP file extension

3GPP Multimedia File

Video Files