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

ASX file extension

Microsoft ASF Redirector File

Video Files

BAT file extension

DOS Batch File

Executable Files

C file extension

C/C++ Source Code File

Developer Files

CGI file extension

Common Gateway Interface Script

Executable Files

CSV file extension

Comma Separated Values File

Data Files

DDS file extension

DirectDraw Surface

Raster Image Files

FLA file extension

Adobe Flash Animation

Developer Files

LUA file extension

Lua Source File

Developer Files

MDB file extension

Microsoft Access Database

Database Files

MID file extension

MIDI File

Audio Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

3DM file extension

Rhino 3D Model

3D Image Files