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

CUE file extension

Cue Sheet File

Disk Image Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

AIF file extension

Audio Interchange File Format

Audio Files

DBF file extension

Database File

Database Files

JAVA file extension

Java Source Code File

Developer Files

M file extension

Objective-C Implementation File

Developer Files

EXE file extension

Windows Executable File

Executable Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

ISO file extension

Disc Image File

Disk Image Files

PRF file extension

Outlook Profile File

Settings Files

3G2 file extension

3GPP2 Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

TTF file extension

TrueType Font

Font Files

PHP file extension

PHP Source Code File

Web Files

UUE file extension

Uuencoded File

Encoded Files