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

PRF file extension

Outlook Profile File

Settings Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

MDB file extension

Microsoft Access Database

Database Files

CRX file extension

Chrome Extension

Plugin Files

CUE file extension

Cue Sheet File

Disk Image Files

PPS file extension

PowerPoint Slide Show

Data Files

CSS file extension

Cascading Style Sheet

Web Files

DB file extension

Database File

Database Files

PART file extension

Partially Downloaded File

Misc Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

SRT file extension

SubRip Subtitle File

Video Files

INI file extension

Windows Initialization File

Settings Files

JAVA file extension

Java Source Code File

Developer Files

DRV file extension

Device Driver

System Files

7Z file extension

7-Zip Compressed File

Compressed Files