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

C file extension

C/C++ Source Code File

Developer Files

APP file extension

Mac OS X Application

Executable Files

BIN file extension

Binary Disc Image

Disk Image Files

XML file extension

XML File

Data Files

GADGET file extension

Windows Gadget

Executable Files

VCXPROJ file extension

Visual C++ Project

Developer Files

PY file extension

Python Script

Developer Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

AI file extension

Adobe Illustrator File

Vector Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

CUR file extension

Windows Cursor

System Files

VB file extension

VBScript File

Executable Files

M4V file extension

iTunes Video File

Video Files

M4A file extension

MPEG-4 Audio File

Audio Files

EPUB file extension

Open eBook File

eBook Files