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

CUR file extension

Windows Cursor

System Files

GBR file extension

Gerber File

Data Files

GPX file extension

GPS Exchange File

GIS Files

INDD file extension

Adobe InDesign Document

Layout Files

JS file extension

JavaScript File

Web Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

ODT file extension

OpenDocument Text Document

Text Files

PART file extension

Partially Downloaded File

Misc Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

SLN file extension

Visual Studio Solution File

Developer Files

TORRENT file extension

BitTorrent File

Misc Files

TTF file extension

TrueType Font

Font Files

VOB file extension

DVD Video Object File

Video Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files