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

BIN file extension

Binary Disc Image

Disk Image Files

DBF file extension

Database File

Database Files

DTD file extension

Document Type Definition File

Developer Files

GZ file extension

Gnu Zipped Archive

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

M4V file extension

iTunes Video File

Video Files

MDF file extension

Media Disc Image File

Disk Image Files

PIF file extension

Program Information File

Executable Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PY file extension

Python Script

Developer Files

RSS file extension

Rich Site Summary

Web Files

SH file extension

Bash Shell Script

Developer Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

3DS file extension

3D Studio Scene

3D Image Files

3G2 file extension

3GPP2 Multimedia File

Video Files