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

BIN file extension

Binary Disc Image

Disk Image Files

CS file extension

Visual C# Source Code File

Developer Files

CUE file extension

Cue Sheet File

Disk Image Files

DNG file extension

Digital Negative Image File

Camera Raw Files

GAM file extension

Saved Game File

Game Files

JSP file extension

Java Server Page

Web Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPT file extension

PowerPoint Presentation

Data Files

PY file extension

Python Script

Developer Files

RA file extension

Real Audio File

Audio Files

SH file extension

Bash Shell Script

Developer Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files