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

7Z file extension

7-Zip Compressed File

Compressed Files

CFG file extension

Configuration File

Settings Files

ZIPX file extension

Extended Zip File

Compressed Files

SQL file extension

Structured Query Language Data File

Database Files

CSS file extension

Cascading Style Sheet

Web Files

MSG file extension

Outlook Mail Message

Text Files

DEB file extension

Debian Software Package

Compressed Files

WMA file extension

Windows Media Audio File

Audio Files

C file extension

C/C++ Source Code File

Developer Files

MDB file extension

Microsoft Access Database

Database Files

PDB file extension

Program Database

Database Files

M file extension

Objective-C Implementation File

Developer Files

LUA file extension

Lua Source File

Developer Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

PL file extension

Perl Script

Developer Files