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

BMP file extension

Bitmap Image File

Raster Image Files

NES file extension

Nintendo (NES) ROM File

Game Files

SDF file extension

Standard Data File

Data Files

VCXPROJ file extension

Visual C++ Project

Developer Files

BAK file extension

Backup File

Backup Files

7Z file extension

7-Zip Compressed File

Compressed Files

DDS file extension

DirectDraw Surface

Raster Image Files

RSS file extension

Rich Site Summary

Web Files

FLA file extension

Adobe Flash Animation

Developer Files

BAT file extension

DOS Batch File

Executable Files

PPT file extension

PowerPoint Presentation

Data Files

HTM file extension

Hypertext Markup Language File

Web Files

WMV file extension

Windows Media Video File

Video Files

GZ file extension

Gnu Zipped Archive

Compressed Files

DWG file extension

AutoCAD Drawing Database File

CAD Files