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

ASPX file extension

Active Server Page Extended File

Web Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CGI file extension

Common Gateway Interface Script

Executable Files

CSV file extension

Comma Separated Values File

Data Files

CUR file extension

Windows Cursor

System Files

EXE file extension

Windows Executable File

Executable Files

GAM file extension

Saved Game File

Game Files

JSP file extension

Java Server Page

Web Files

KML file extension

Keyhole Markup Language File

GIS Files

PART file extension

Partially Downloaded File

Misc Files

PIF file extension

Program Information File

Executable Files

PL file extension

Perl Script

Developer Files

SH file extension

Bash Shell Script

Developer Files

SITX file extension

StuffIt X Archive

Compressed Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files