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

AI file extension

Adobe Illustrator File

Vector Image Files

CRX file extension

Chrome Extension

Plugin Files

CSV file extension

Comma Separated Values File

Data Files

CUR file extension

Windows Cursor

System Files

DLL file extension

Dynamic Link Library

System Files

DOC file extension

Microsoft Word Document

Text Files

DOC# file extension

Microsoft Word Document

Text Files

FON file extension

Generic Font File

Font Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

HTM file extension

Hypertext Markup Language File

Web Files

HTML file extension

Hypertext Markup Language File

Web Files

JSP file extension

Java Server Page

Web Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

TMP file extension

Temporary File

Backup Files

VCF file extension

vCard File

Data Files