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

APK file extension

Android Package File

Executable Files

ASP file extension

Active Server Page

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

CER file extension

Internet Security Certificate

Web Files

COM file extension

DOS Command File

Executable Files

DEB file extension

Debian Software Package

Compressed Files

GPX file extension

GPS Exchange File

GIS Files

ICO file extension

Icon File

System Files

LOG file extension

Log File

Text Files

M4V file extension

iTunes Video File

Video Files

ODT file extension

OpenDocument Text Document

Text Files

PAGES file extension

Pages Document

Text Files

PPT file extension

PowerPoint Presentation

Data Files

TTF file extension

TrueType Font

Font Files

WMV file extension

Windows Media Video File

Video Files