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

CFG file extension

Configuration File

Settings Files

COM file extension

DOS Command File

Executable Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

ISO file extension

Disc Image File

Disk Image Files

LNK file extension

Windows File Shortcut

System Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PRF file extension

Outlook Profile File

Settings Files

SLN file extension

Visual Studio Solution File

Developer Files

SWF file extension

Shockwave Flash Movie

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

WAV file extension

WAVE Audio File

Audio Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files

3G2 file extension

3GPP2 Multimedia File

Video Files