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

ASF file extension

Advanced Systems Format File

Video Files

ASPX file extension

Active Server Page Extended File

Web Files

AVI file extension

Audio Video Interleave File

Video Files

COM file extension

DOS Command File

Executable Files

CRX file extension

Chrome Extension

Plugin Files

H file extension

C/C++/Objective-C Header File

Developer Files

INDD file extension

Adobe InDesign Document

Layout Files

MAX file extension

3ds Max Scene File

3D Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MP4 file extension

MPEG-4 Video File

Video Files

PART file extension

Partially Downloaded File

Misc Files

PIF file extension

Program Information File

Executable Files

SLN file extension

Visual Studio Solution File

Developer Files

TMP file extension

Temporary File

Backup Files

WAV file extension

WAVE Audio File

Audio Files