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

EXE file extension

Windows Executable File

Executable Files

MDB file extension

Microsoft Access Database

Database Files

XML file extension

XML File

Data Files

LOG file extension

Log File

Text Files

3DS file extension

3D Studio Scene

3D Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

LNK file extension

Windows File Shortcut

System Files

WMA file extension

Windows Media Audio File

Audio Files

OTF file extension

OpenType Font

Font Files

7Z file extension

7-Zip Compressed File

Compressed Files

JPG file extension

JPEG Image

Raster Image Files

DLL file extension

Dynamic Link Library

System Files

AI file extension

Adobe Illustrator File

Vector Image Files

IBOOKS file extension

Multi-Touch iBook

Data Files

FLA file extension

Adobe Flash Animation

Developer Files