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

CRX file extension

Chrome Extension

Plugin Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

DAT file extension

Data File

Data Files

DRV file extension

Device Driver

System Files

CLASS file extension

Java Class File

Developer Files

M4V file extension

iTunes Video File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

C file extension

C/C++ Source Code File

Developer Files

CPP file extension

C++ Source Code File

Developer Files

MPA file extension

MPEG-2 Audio File

Audio Files

PPT file extension

PowerPoint Presentation

Data Files

ZIP file extension

Zipped File

Compressed Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

BAK file extension

Backup File

Backup Files

GADGET file extension

Windows Gadget

Executable Files