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

TXT file extension

Plain Text File

Text Files

MP3 file extension

MP3 Audio File

Audio Files

DB file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

GED file extension

GEDCOM Genealogy Data File

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files

MID file extension

MIDI File

Audio Files

CSS file extension

Cascading Style Sheet

Web Files

ROM file extension

N64 Game ROM File

Game Files

WMV file extension

Windows Media Video File

Video Files

MPA file extension

MPEG-2 Audio File

Audio Files

SQL file extension

Structured Query Language Data File

Database Files

ASPX file extension

Active Server Page Extended File

Web Files

DEB file extension

Debian Software Package

Compressed Files