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

VCXPROJ file extension

Visual C++ Project

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files

VB file extension

VBScript File

Executable Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

DOC file extension

Microsoft Word Document

Text Files

THM file extension

Thumbnail Image File

Raster Image Files

DB file extension

Database File

Database Files

GADGET file extension

Windows Gadget

Executable Files

MDB file extension

Microsoft Access Database

Database Files

MAX file extension

3ds Max Scene File

3D Image Files

M file extension

Objective-C Implementation File

Developer Files

SAV file extension

Saved Game

Game Files

PAGES file extension

Pages Document

Text Files

JSP file extension

Java Server Page

Web Files

DMP file extension

Windows Memory Dump

System Files