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

COM file extension

DOS Command File

Executable Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DAT file extension

Data File

Data Files

FLA file extension

Adobe Flash Animation

Developer Files

GPX file extension

GPS Exchange File

GIS Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MAX file extension

3ds Max Scene File

3D Image Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

TOAST file extension

Toast Disc Image

Disk Image Files

VB file extension

VBScript File

Executable Files

WMV file extension

Windows Media Video File

Video Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

ZIP file extension

Zipped File

Compressed Files