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

APP file extension

Mac OS X Application

Executable Files

CPP file extension

C++ Source Code File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CUR file extension

Windows Cursor

System Files

DDS file extension

DirectDraw Surface

Raster Image Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

EXE file extension

Windows Executable File

Executable Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

ICNS file extension

Mac OS X Icon Resource File

System Files

MP3 file extension

MP3 Audio File

Audio Files

SDF file extension

Standard Data File

Data Files

SRT file extension

SubRip Subtitle File

Video Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files

VB file extension

VBScript File

Executable Files