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

AIF file extension

Audio Interchange File Format

Audio Files

ASPX file extension

Active Server Page Extended File

Web Files

ASX file extension

Microsoft ASF Redirector File

Video Files

BAK file extension

Backup File

Backup Files

BMP file extension

Bitmap Image File

Raster Image Files

CUE file extension

Cue Sheet File

Disk Image Files

DMP file extension

Windows Memory Dump

System Files

FLV file extension

Flash Video File

Video Files

GBR file extension

Gerber File

Data Files

JAVA file extension

Java Source Code File

Developer Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

ROM file extension

N64 Game ROM File

Game Files

RPM file extension

Red Hat Package Manager File

Compressed Files

TTF file extension

TrueType Font

Font Files