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

AVI file extension

Audio Video Interleave File

Video Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

FLV file extension

Flash Video File

Video Files

GADGET file extension

Windows Gadget

Executable Files

GBR file extension

Gerber File

Data Files

ISO file extension

Disc Image File

Disk Image Files

MDB file extension

Microsoft Access Database

Database Files

MID file extension

MIDI File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

SAV file extension

Saved Game

Game Files

TARGZ file extension

Compressed Tarball File

Compressed Files

WSF file extension

Windows Script File

Executable Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files