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

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CSV file extension

Comma Separated Values File

Data Files

DDS file extension

DirectDraw Surface

Raster Image Files

HTML file extension

Hypertext Markup Language File

Web Files

ICS file extension

iCalendar File

Misc Files

M4V file extension

iTunes Video File

Video Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MOV file extension

Apple QuickTime Movie

Video Files

PKG file extension

Mac OS X Installer Package

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

TIF file extension

Tagged Image File

Raster Image Files

UUE file extension

Uuencoded File

Encoded Files

VB file extension

VBScript File

Executable Files

ZIP file extension

Zipped File

Compressed Files