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

AI file extension

Adobe Illustrator File

Vector Image Files

CFM file extension

ColdFusion Markup File

Web Files

DEM file extension

Video Game Demo File

Game Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

HTM file extension

Hypertext Markup Language File

Web Files

ICS file extension

iCalendar File

Misc Files

LOG file extension

Log File

Text Files

MSI file extension

Windows Installer Package

Misc Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

PY file extension

Python Script

Developer Files

RSS file extension

Rich Site Summary

Web Files

SQL file extension

Structured Query Language Data File

Database Files

YUV file extension

YUV Encoded Image File

Raster Image Files

ZIPX file extension

Extended Zip File

Compressed Files