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

DAT file extension

Data File

Data Files

DLL file extension

Dynamic Link Library

System Files

DMP file extension

Windows Memory Dump

System Files

DOC# file extension

Microsoft Word Document

Text Files

FNT file extension

Windows Font File

Font Files

GAM file extension

Saved Game File

Game Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IFF file extension

Interchange File Format

Audio Files

JAVA file extension

Java Source Code File

Developer Files

MPA file extension

MPEG-2 Audio File

Audio Files

PNG file extension

Portable Network Graphic

Raster Image Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SYS file extension

Windows System File

System Files

VB file extension

VBScript File

Executable Files

3DM file extension

Rhino 3D Model

3D Image Files