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

AIF file extension

Audio Interchange File Format

Audio Files

ASX file extension

Microsoft ASF Redirector File

Video Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CUE file extension

Cue Sheet File

Disk Image Files

FLA file extension

Adobe Flash Animation

Developer Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

INI file extension

Windows Initialization File

Settings Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

LUA file extension

Lua Source File

Developer Files

MID file extension

MIDI File

Audio Files

ROM file extension

N64 Game ROM File

Game Files

TARGZ file extension

Compressed Tarball File

Compressed Files

WMA file extension

Windows Media Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

3G2 file extension

3GPP2 Multimedia File

Video Files