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

PS file extension

PostScript File

Vector Image Files

SDF file extension

Standard Data File

Data Files

C file extension

C/C++ Source Code File

Developer Files

PKG file extension

Mac OS X Installer Package

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

DOC file extension

Microsoft Word Document

Text Files

BAT file extension

DOS Batch File

Executable Files

DRV file extension

Device Driver

System Files

CBR file extension

Comic Book RAR Archive

Compressed Files

XML file extension

XML File

Data Files

DOC# file extension

Microsoft Word Document

Text Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

DMP file extension

Windows Memory Dump

System Files

BAK file extension

Backup File

Backup Files

TORRENT file extension

BitTorrent File

Misc Files