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

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

XML file extension

XML File

Data Files

PHP file extension

PHP Source Code File

Web Files

WSF file extension

Windows Script File

Executable Files

7Z file extension

7-Zip Compressed File

Compressed Files

ICO file extension

Icon File

System Files

MPG file extension

MPEG Video File

Video Files

DXF file extension

Drawing Exchange Format File

CAD Files

PNG file extension

Portable Network Graphic

Raster Image Files

RA file extension

Real Audio File

Audio Files

XCODEPROJ file extension

Xcode Project

Developer Files

SRT file extension

SubRip Subtitle File

Video Files

HTM file extension

Hypertext Markup Language File

Web Files

DB file extension

Database File

Database Files

YUV file extension

YUV Encoded Image File

Raster Image Files