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

XML file extension

XML File

Data Files

LOG file extension

Log File

Text Files

DOC# file extension

Microsoft Word Document

Text Files

GED file extension

GEDCOM Genealogy Data File

Data Files

VB file extension

VBScript File

Executable Files

PY file extension

Python Script

Developer Files

PAGES file extension

Pages Document

Text Files

AZW file extension

Amazon Kindle eBook File

eBook Files

FLA file extension

Adobe Flash Animation

Developer Files

PNG file extension

Portable Network Graphic

Raster Image Files

ICNS file extension

Mac OS X Icon Resource File

System Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

DXF file extension

Drawing Exchange Format File

CAD Files

ROM file extension

N64 Game ROM File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files