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

CFG file extension

Configuration File

Settings Files

CUE file extension

Cue Sheet File

Disk Image Files

DEM file extension

Video Game Demo File

Game Files

DLL file extension

Dynamic Link Library

System Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

JAVA file extension

Java Source Code File

Developer Files

M file extension

Objective-C Implementation File

Developer Files

MAX file extension

3ds Max Scene File

3D Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MOBI file extension

Mobipocket eBook

eBook Files

PDF file extension

Portable Document Format File

Layout Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RA file extension

Real Audio File

Audio Files

SAV file extension

Saved Game

Game Files

WPS file extension

Microsoft Works Word Processor Document

Text Files