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

ASP file extension

Active Server Page

Web Files

DOC file extension

Microsoft Word Document

Text Files

DXF file extension

Drawing Exchange Format File

CAD Files

FON file extension

Generic Font File

Font Files

ICS file extension

iCalendar File

Misc Files

M4A file extension

MPEG-4 Audio File

Audio Files

OTF file extension

OpenType Font

Font Files

PART file extension

Partially Downloaded File

Misc Files

PIF file extension

Program Information File

Executable Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RSS file extension

Rich Site Summary

Web Files

RTF file extension

Rich Text Format File

Text Files

TGA file extension

Targa Graphic

Raster Image Files

VOB file extension

DVD Video Object File

Video Files

3G2 file extension

3GPP2 Multimedia File

Video Files