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

CAB file extension

Windows Cabinet File

System Files

COM file extension

DOS Command File

Executable Files

DAT file extension

Data File

Data Files

GADGET file extension

Windows Gadget

Executable Files

GAM file extension

Saved Game File

Game Files

GPX file extension

GPS Exchange File

GIS Files

MP4 file extension

MPEG-4 Video File

Video Files

PNG file extension

Portable Network Graphic

Raster Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

SWF file extension

Shockwave Flash Movie

Video Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TTF file extension

TrueType Font

Font Files

WAV file extension

WAVE Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files