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

RSS file extension

Rich Site Summary

Web Files

FNT file extension

Windows Font File

Font Files

SLN file extension

Visual Studio Solution File

Developer Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

SITX file extension

StuffIt X Archive

Compressed Files

DNG file extension

Digital Negative Image File

Camera Raw Files

THM file extension

Thumbnail Image File

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

PS file extension

PostScript File

Vector Image Files

MP3 file extension

MP3 Audio File

Audio Files

TEX file extension

LaTeX Source Document

Text Files

SH file extension

Bash Shell Script

Developer Files

LOG file extension

Log File

Text Files