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

AZW file extension

Amazon Kindle eBook File

eBook Files

C file extension

C/C++ Source Code File

Developer Files

CFG file extension

Configuration File

Settings Files

EXE file extension

Windows Executable File

Executable Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

JAR file extension

Java Archive File

Executable Files

KEY file extension

Keynote Presentation

Data Files

LUA file extension

Lua Source File

Developer Files

PNG file extension

Portable Network Graphic

Raster Image Files

PRF file extension

Outlook Profile File

Settings Files

RTF file extension

Rich Text Format File

Text Files

SRT file extension

SubRip Subtitle File

Video Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WSF file extension

Windows Script File

Executable Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files