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

BAT file extension

DOS Batch File

Executable Files

CLASS file extension

Java Class File

Developer Files

DEB file extension

Debian Software Package

Compressed Files

DRV file extension

Device Driver

System Files

DTD file extension

Document Type Definition File

Developer Files

GAM file extension

Saved Game File

Game Files

HTM file extension

Hypertext Markup Language File

Web Files

JAR file extension

Java Archive File

Executable Files

LOG file extension

Log File

Text Files

PIF file extension

Program Information File

Executable Files

PRF file extension

Outlook Profile File

Settings Files

TMP file extension

Temporary File

Backup Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WSF file extension

Windows Script File

Executable Files