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

PL file extension

Perl Script

Developer Files

PS file extension

PostScript File

Vector Image Files

UUE file extension

Uuencoded File

Encoded Files

SLN file extension

Visual Studio Solution File

Developer Files

FNT file extension

Windows Font File

Font Files

TEX file extension

LaTeX Source Document

Text Files

DEB file extension

Debian Software Package

Compressed Files

JAR file extension

Java Archive File

Executable Files

CRX file extension

Chrome Extension

Plugin Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

WMA file extension

Windows Media Audio File

Audio Files

TXT file extension

Plain Text File

Text Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

KEY file extension

Keynote Presentation

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files