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

CPL file extension

Windows Control Panel Item

System Files

CS file extension

Visual C# Source Code File

Developer Files

DBF file extension

Database File

Database Files

DRV file extension

Device Driver

System Files

FON file extension

Generic Font File

Font Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IFF file extension

Interchange File Format

Audio Files

JAR file extension

Java Archive File

Executable Files

MDB file extension

Microsoft Access Database

Database Files

MOV file extension

Apple QuickTime Movie

Video Files

PCT file extension

Picture File

Layout Files

TTF file extension

TrueType Font

Font Files

TXT file extension

Plain Text File

Text Files

WPD file extension

WordPerfect Document

Text Files

WSF file extension

Windows Script File

Executable Files