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

CPL file extension

Windows Control Panel Item

System Files

DLL file extension

Dynamic Link Library

System Files

EPUB file extension

Open eBook File

eBook Files

EXE file extension

Windows Executable File

Executable Files

GPX file extension

GPS Exchange File

GIS Files

IFF file extension

Interchange File Format

Audio Files

INDD file extension

Adobe InDesign Document

Layout Files

LOG file extension

Log File

Text Files

LUA file extension

Lua Source File

Developer Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SQL file extension

Structured Query Language Data File

Database Files

TIF file extension

Tagged Image File

Raster Image Files

TMP file extension

Temporary File

Backup Files