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

AVI file extension

Audio Video Interleave File

Video Files

BAT file extension

DOS Batch File

Executable Files

DDS file extension

DirectDraw Surface

Raster Image Files

DEM file extension

Video Game Demo File

Game Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

FNT file extension

Windows Font File

Font Files

GED file extension

GEDCOM Genealogy Data File

Data Files

H file extension

C/C++/Objective-C Header File

Developer Files

JAVA file extension

Java Source Code File

Developer Files

M4A file extension

MPEG-4 Audio File

Audio Files

SITX file extension

StuffIt X Archive

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

TGA file extension

Targa Graphic

Raster Image Files

TMP file extension

Temporary File

Backup Files

VCXPROJ file extension

Visual C++ Project

Developer Files