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

WPS file extension

Microsoft Works Word Processor Document

Text Files

WPD file extension

WordPerfect Document

Text Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

PNG file extension

Portable Network Graphic

Raster Image Files

ASF file extension

Advanced Systems Format File

Video Files

XCODEPROJ file extension

Xcode Project

Developer Files

GZ file extension

Gnu Zipped Archive

Compressed Files

WSF file extension

Windows Script File

Executable Files

TOAST file extension

Toast Disc Image

Disk Image Files

CLASS file extension

Java Class File

Developer Files

DB file extension

Database File

Database Files

GED file extension

GEDCOM Genealogy Data File

Data Files

LUA file extension

Lua Source File

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files