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

CBR file extension

Comic Book RAR Archive

Compressed Files

CFG file extension

Configuration File

Settings Files

DB file extension

Database File

Database Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

DMP file extension

Windows Memory Dump

System Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ICS file extension

iCalendar File

Misc Files

KML file extension

Keyhole Markup Language File

GIS Files

PPS file extension

PowerPoint Slide Show

Data Files

SDF file extension

Standard Data File

Data Files

SYS file extension

Windows System File

System Files

TTF file extension

TrueType Font

Font Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files

YUV file extension

YUV Encoded Image File

Raster Image Files