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

SDF file extension

Standard Data File

Data Files

TIF file extension

Tagged Image File

Raster Image Files

MSG file extension

Outlook Mail Message

Text Files

CGI file extension

Common Gateway Interface Script

Executable Files

SRT file extension

SubRip Subtitle File

Video Files

WMA file extension

Windows Media Audio File

Audio Files

M file extension

Objective-C Implementation File

Developer Files

VOB file extension

DVD Video Object File

Video Files

AIF file extension

Audio Interchange File Format

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

DDS file extension

DirectDraw Surface

Raster Image Files

PY file extension

Python Script

Developer Files

ICS file extension

iCalendar File

Misc Files

FLV file extension

Flash Video File

Video Files

C file extension

C/C++ Source Code File

Developer Files