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

CRX file extension

Chrome Extension

Plugin Files

VB file extension

VBScript File

Executable Files

CUR file extension

Windows Cursor

System Files

BAT file extension

DOS Batch File

Executable Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

DB file extension

Database File

Database Files

TTF file extension

TrueType Font

Font Files

UUE file extension

Uuencoded File

Encoded Files

DOC file extension

Microsoft Word Document

Text Files

ROM file extension

N64 Game ROM File

Game Files

CPP file extension

C++ Source Code File

Developer Files

LOG file extension

Log File

Text Files

CFG file extension

Configuration File

Settings Files

7Z file extension

7-Zip Compressed File

Compressed Files

PKG file extension

Mac OS X Installer Package

Compressed Files