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

ACCDB file extension

Access 2007 Database File

Database Files

CPL file extension

Windows Control Panel Item

System Files

CRX file extension

Chrome Extension

Plugin Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

ICS file extension

iCalendar File

Misc Files

INDD file extension

Adobe InDesign Document

Layout Files

M4A file extension

MPEG-4 Audio File

Audio Files

MAX file extension

3ds Max Scene File

3D Image Files

PDB file extension

Program Database

Database Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SLN file extension

Visual Studio Solution File

Developer Files

TEX file extension

LaTeX Source Document

Text Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XCODEPROJ file extension

Xcode Project

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files