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

DAT file extension

Data File

Data Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

FNT file extension

Windows Font File

Font Files

GED file extension

GEDCOM Genealogy Data File

Data Files

ICO file extension

Icon File

System Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PCT file extension

Picture File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

TGA file extension

Targa Graphic

Raster Image Files

TXT file extension

Plain Text File

Text Files

VB file extension

VBScript File

Executable Files

VOB file extension

DVD Video Object File

Video Files

WAV file extension

WAVE Audio File

Audio Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files