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

COM file extension

DOS Command File

Executable Files

DDS file extension

DirectDraw Surface

Raster Image Files

GADGET file extension

Windows Gadget

Executable Files

JAR file extension

Java Archive File

Executable Files

JSP file extension

Java Server Page

Web Files

LOG file extension

Log File

Text Files

M4V file extension

iTunes Video File

Video Files

PDB file extension

Program Database

Database Files

RSS file extension

Rich Site Summary

Web Files

TAR file extension

Consolidated Unix File Archive

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WSF file extension

Windows Script File

Executable Files