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

THM file extension

Thumbnail Image File

Raster Image Files

GED file extension

GEDCOM Genealogy Data File

Data Files

CS file extension

Visual C# Source Code File

Developer Files

PY file extension

Python Script

Developer Files

UUE file extension

Uuencoded File

Encoded Files

INI file extension

Windows Initialization File

Settings Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PS file extension

PostScript File

Vector Image Files

PNG file extension

Portable Network Graphic

Raster Image Files

PRF file extension

Outlook Profile File

Settings Files

7Z file extension

7-Zip Compressed File

Compressed Files

CFG file extension

Configuration File

Settings Files

VCF file extension

vCard File

Data Files

RM file extension

Real Media File

Video Files

CRX file extension

Chrome Extension

Plugin Files