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

CLASS file extension

Java Class File

Developer Files

CRX file extension

Chrome Extension

Plugin Files

DOC# file extension

Microsoft Word Document

Text Files

GZ file extension

Gnu Zipped Archive

Compressed Files

JAR file extension

Java Archive File

Executable Files

MPA file extension

MPEG-2 Audio File

Audio Files

MPG file extension

MPEG Video File

Video Files

PL file extension

Perl Script

Developer Files

RM file extension

Real Media File

Video Files

RSS file extension

Rich Site Summary

Web Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SWF file extension

Shockwave Flash Movie

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

TTF file extension

TrueType Font

Font Files