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

ASP file extension

Active Server Page

Web Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

ISO file extension

Disc Image File

Disk Image Files

IBOOKS file extension

Multi-Touch iBook

Data Files

JS file extension

JavaScript File

Web Files

BIN file extension

Binary Disc Image

Disk Image Files

TXT file extension

Plain Text File

Text Files

DRV file extension

Device Driver

System Files

M file extension

Objective-C Implementation File

Developer Files

ASPX file extension

Active Server Page Extended File

Web Files

JAVA file extension

Java Source Code File

Developer Files

TAR file extension

Consolidated Unix File Archive

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files