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

TGA file extension

Targa Graphic

Raster Image Files

TTF file extension

TrueType Font

Font Files

ICNS file extension

Mac OS X Icon Resource File

System Files

SWF file extension

Shockwave Flash Movie

Video Files

PY file extension

Python Script

Developer Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

GZ file extension

Gnu Zipped Archive

Compressed Files

MPG file extension

MPEG Video File

Video Files

PKG file extension

Mac OS X Installer Package

Compressed Files

CUE file extension

Cue Sheet File

Disk Image Files

CRX file extension

Chrome Extension

Plugin Files

THM file extension

Thumbnail Image File

Raster Image Files

FNT file extension

Windows Font File

Font Files