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

C file extension

C/C++ Source Code File

Developer Files

CSR file extension

Certificate Signing Request File

Web Files

DB file extension

Database File

Database Files

DEM file extension

Video Game Demo File

Game Files

DOC file extension

Microsoft Word Document

Text Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

JAVA file extension

Java Source Code File

Developer Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PNG file extension

Portable Network Graphic

Raster Image Files

SRT file extension

SubRip Subtitle File

Video Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

UUE file extension

Uuencoded File

Encoded Files

VCXPROJ file extension

Visual C++ Project

Developer Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

ZIPX file extension

Extended Zip File

Compressed Files