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

TARGZ file extension

Compressed Tarball File

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

SQL file extension

Structured Query Language Data File

Database Files

WMA file extension

Windows Media Audio File

Audio Files

PKG file extension

Mac OS X Installer Package

Compressed Files

MDB file extension

Microsoft Access Database

Database Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

ISO file extension

Disc Image File

Disk Image Files

LOG file extension

Log File

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

WSF file extension

Windows Script File

Executable Files

MPG file extension

MPEG Video File

Video Files

SAV file extension

Saved Game

Game Files

3DS file extension

3D Studio Scene

3D Image Files

GPX file extension

GPS Exchange File

GIS Files