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

ASF file extension

Advanced Systems Format File

Video Files

CGI file extension

Common Gateway Interface Script

Executable Files

DDS file extension

DirectDraw Surface

Raster Image Files

FLV file extension

Flash Video File

Video Files

FNT file extension

Windows Font File

Font Files

GAM file extension

Saved Game File

Game Files

GED file extension

GEDCOM Genealogy Data File

Data Files

INDD file extension

Adobe InDesign Document

Layout Files

MDF file extension

Media Disc Image File

Disk Image Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TORRENT file extension

BitTorrent File

Misc Files

UUE file extension

Uuencoded File

Encoded Files

XML file extension

XML File

Data Files

YUV file extension

YUV Encoded Image File

Raster Image Files