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

MSG file extension

Outlook Mail Message

Text Files

ICO file extension

Icon File

System Files

MSI file extension

Windows Installer Package

Misc Files

7Z file extension

7-Zip Compressed File

Compressed Files

ASP file extension

Active Server Page

Web Files

TIFF file extension

Tagged Image File Format

Raster Image Files

ASF file extension

Advanced Systems Format File

Video Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

LUA file extension

Lua Source File

Developer Files

APK file extension

Android Package File

Executable Files

MID file extension

MIDI File

Audio Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

PDB file extension

Program Database

Database Files