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

BIN file extension

Binary Disc Image

Disk Image Files

CFG file extension

Configuration File

Settings Files

DRV file extension

Device Driver

System Files

EPUB file extension

Open eBook File

eBook Files

GED file extension

GEDCOM Genealogy Data File

Data Files

JS file extension

JavaScript File

Web Files

LUA file extension

Lua Source File

Developer Files

M3U file extension

Media Playlist File

Audio Files

M4V file extension

iTunes Video File

Video Files

PART file extension

Partially Downloaded File

Misc Files

RTF file extension

Rich Text Format File

Text Files

THM file extension

Thumbnail Image File

Raster Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WMV file extension

Windows Media Video File

Video Files

YUV file extension

YUV Encoded Image File

Raster Image Files