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

BAT file extension

DOS Batch File

Executable Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CSR file extension

Certificate Signing Request File

Web Files

CUE file extension

Cue Sheet File

Disk Image Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

FNT file extension

Windows Font File

Font Files

GAM file extension

Saved Game File

Game Files

GZ file extension

Gnu Zipped Archive

Compressed Files

ICNS file extension

Mac OS X Icon Resource File

System Files

JSP file extension

Java Server Page

Web Files

KML file extension

Keyhole Markup Language File

GIS Files

LUA file extension

Lua Source File

Developer Files

TEX file extension

LaTeX Source Document

Text Files

WAV file extension

WAVE Audio File

Audio Files

YUV file extension

YUV Encoded Image File

Raster Image Files