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

HTM file extension

Hypertext Markup Language File

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CSR file extension

Certificate Signing Request File

Web Files

ASF file extension

Advanced Systems Format File

Video Files

TIF file extension

Tagged Image File

Raster Image Files

MP3 file extension

MP3 Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

VCXPROJ file extension

Visual C++ Project

Developer Files

PHP file extension

PHP Source Code File

Web Files

CFG file extension

Configuration File

Settings Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

GPX file extension

GPS Exchange File

GIS Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

FLV file extension

Flash Video File

Video Files