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

GZ file extension

Gnu Zipped Archive

Compressed Files

TXT file extension

Plain Text File

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

3G2 file extension

3GPP2 Multimedia File

Video Files

DRV file extension

Device Driver

System Files

GAM file extension

Saved Game File

Game Files

PNG file extension

Portable Network Graphic

Raster Image Files

ASP file extension

Active Server Page

Web Files

DEB file extension

Debian Software Package

Compressed Files

PKG file extension

Mac OS X Installer Package

Compressed Files

TMP file extension

Temporary File

Backup Files

LOG file extension

Log File

Text Files

DBF file extension

Database File

Database Files

M file extension

Objective-C Implementation File

Developer Files

SAV file extension

Saved Game

Game Files