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

DDS file extension

DirectDraw Surface

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

XCODEPROJ file extension

Xcode Project

Developer Files

TMP file extension

Temporary File

Backup Files

TIF file extension

Tagged Image File

Raster Image Files

HTML file extension

Hypertext Markup Language File

Web Files

MPG file extension

MPEG Video File

Video Files

CRX file extension

Chrome Extension

Plugin Files

DRV file extension

Device Driver

System Files

TORRENT file extension

BitTorrent File

Misc Files

GBR file extension

Gerber File

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

BIN file extension

Binary Disc Image

Disk Image Files