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

AVI file extension

Audio Video Interleave File

Video Files

BIN file extension

Binary Disc Image

Disk Image Files

DOC file extension

Microsoft Word Document

Text Files

FLA file extension

Adobe Flash Animation

Developer Files

GZ file extension

Gnu Zipped Archive

Compressed Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

MOV file extension

Apple QuickTime Movie

Video Files

PCT file extension

Picture File

Layout Files

PIF file extension

Program Information File

Executable Files

RM file extension

Real Media File

Video Files

SLN file extension

Visual Studio Solution File

Developer Files

TOAST file extension

Toast Disc Image

Disk Image Files

VOB file extension

DVD Video Object File

Video Files

3G2 file extension

3GPP2 Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files