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

BAT file extension

DOS Batch File

Executable Files

COM file extension

DOS Command File

Executable Files

CRX file extension

Chrome Extension

Plugin Files

DAT file extension

Data File

Data Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

FLA file extension

Adobe Flash Animation

Developer Files

FON file extension

Generic Font File

Font Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

NES file extension

Nintendo (NES) ROM File

Game Files

PS file extension

PostScript File

Vector Image Files

RA file extension

Real Audio File

Audio Files

TIFF file extension

Tagged Image File Format

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

XLR file extension

Works Spreadsheet

Spreadsheet Files