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

ASX file extension

Microsoft ASF Redirector File

Video Files

CER file extension

Internet Security Certificate

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

MOV file extension

Apple QuickTime Movie

Video Files

MP4 file extension

MPEG-4 Video File

Video Files

PAGES file extension

Pages Document

Text Files

PCT file extension

Picture File

Layout Files

PL file extension

Perl Script

Developer Files

PPT file extension

PowerPoint Presentation

Data Files

SDF file extension

Standard Data File

Data Files

TORRENT file extension

BitTorrent File

Misc Files

VB file extension

VBScript File

Executable Files

VCF file extension

vCard File

Data Files

VCXPROJ file extension

Visual C++ Project

Developer Files

XLR file extension

Works Spreadsheet

Spreadsheet Files