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

SH file extension

Bash Shell Script

Developer Files

COM file extension

DOS Command File

Executable Files

DXF file extension

Drawing Exchange Format File

CAD Files

CLASS file extension

Java Class File

Developer Files

EXE file extension

Windows Executable File

Executable Files

RM file extension

Real Media File

Video Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

DEB file extension

Debian Software Package

Compressed Files

DOC file extension

Microsoft Word Document

Text Files

FON file extension

Generic Font File

Font Files

ICO file extension

Icon File

System Files

7Z file extension

7-Zip Compressed File

Compressed Files

TTF file extension

TrueType Font

Font Files

PPS file extension

PowerPoint Slide Show

Data Files

WSF file extension

Windows Script File

Executable Files