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

CBR file extension

Comic Book RAR Archive

Compressed Files

EXE file extension

Windows Executable File

Executable Files

GPX file extension

GPS Exchange File

GIS Files

INI file extension

Windows Initialization File

Settings Files

M4V file extension

iTunes Video File

Video Files

MOBI file extension

Mobipocket eBook

eBook Files

PY file extension

Python Script

Developer Files

RA file extension

Real Audio File

Audio Files

SH file extension

Bash Shell Script

Developer Files

WMV file extension

Windows Media Video File

Video Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

XML file extension

XML File

Data Files

3G2 file extension

3GPP2 Multimedia File

Video Files