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

BAT file extension

DOS Batch File

Executable Files

C file extension

C/C++ Source Code File

Developer Files

CAB file extension

Windows Cabinet File

System Files

CFM file extension

ColdFusion Markup File

Web Files

GPX file extension

GPS Exchange File

GIS Files

GZ file extension

Gnu Zipped Archive

Compressed Files

MAX file extension

3ds Max Scene File

3D Image Files

NES file extension

Nintendo (NES) ROM File

Game Files

ODT file extension

OpenDocument Text Document

Text Files

PY file extension

Python Script

Developer Files

SLN file extension

Visual Studio Solution File

Developer Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TMP file extension

Temporary File

Backup Files

TXT file extension

Plain Text File

Text Files

ZIPX file extension

Extended Zip File

Compressed Files