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

SRT file extension

SubRip Subtitle File

Video Files

DB file extension

Database File

Database Files

PCT file extension

Picture File

Layout Files

KEY file extension

Keynote Presentation

Data Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

JSP file extension

Java Server Page

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

FLV file extension

Flash Video File

Video Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CPP file extension

C++ Source Code File

Developer Files

AZW file extension

Amazon Kindle eBook File

eBook Files

3DS file extension

3D Studio Scene

3D Image Files

SITX file extension

StuffIt X Archive

Compressed Files

M4V file extension

iTunes Video File

Video Files

RSS file extension

Rich Site Summary

Web Files