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

BAT file extension

DOS Batch File

Executable Files

C file extension

C/C++ Source Code File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CUR file extension

Windows Cursor

System Files

DLL file extension

Dynamic Link Library

System Files

DOC file extension

Microsoft Word Document

Text Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GADGET file extension

Windows Gadget

Executable Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

ICS file extension

iCalendar File

Misc Files

ODT file extension

OpenDocument Text Document

Text Files

SH file extension

Bash Shell Script

Developer Files

SYS file extension

Windows System File

System Files

3GP file extension

3GPP Multimedia File

Video Files