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

DEB file extension

Debian Software Package

Compressed Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

JSP file extension

Java Server Page

Web Files

LNK file extension

Windows File Shortcut

System Files

MOV file extension

Apple QuickTime Movie

Video Files

PCT file extension

Picture File

Layout Files

PIF file extension

Program Information File

Executable Files

SWF file extension

Shockwave Flash Movie

Video Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files

TXT file extension

Plain Text File

Text Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

XML file extension

XML File

Data Files