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

ZIPX file extension

Extended Zip File

Compressed Files

GED file extension

GEDCOM Genealogy Data File

Data Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SRT file extension

SubRip Subtitle File

Video Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

CPL file extension

Windows Control Panel Item

System Files

WMA file extension

Windows Media Audio File

Audio Files

TARGZ file extension

Compressed Tarball File

Compressed Files

ROM file extension

N64 Game ROM File

Game Files

COM file extension

DOS Command File

Executable Files

TTF file extension

TrueType Font

Font Files

7Z file extension

7-Zip Compressed File

Compressed Files

FLV file extension

Flash Video File

Video Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

INDD file extension

Adobe InDesign Document

Layout Files