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

AZW file extension

Amazon Kindle eBook File

eBook Files

CGI file extension

Common Gateway Interface Script

Executable Files

DAT file extension

Data File

Data Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

ICS file extension

iCalendar File

Misc Files

INDD file extension

Adobe InDesign Document

Layout Files

LNK file extension

Windows File Shortcut

System Files

PDF file extension

Portable Document Format File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RM file extension

Real Media File

Video Files

SWF file extension

Shockwave Flash Movie

Video Files

UUE file extension

Uuencoded File

Encoded Files

VB file extension

VBScript File

Executable Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files