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

APK file extension

Android Package File

Executable Files

ASPX file extension

Active Server Page Extended File

Web Files

CSV file extension

Comma Separated Values File

Data Files

DBF file extension

Database File

Database Files

EXE file extension

Windows Executable File

Executable Files

GED file extension

GEDCOM Genealogy Data File

Data Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

IFF file extension

Interchange File Format

Audio Files

INI file extension

Windows Initialization File

Settings Files

LUA file extension

Lua Source File

Developer Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

RSS file extension

Rich Site Summary

Web Files

TXT file extension

Plain Text File

Text Files

WPD file extension

WordPerfect Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files