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

BAT file extension

DOS Batch File

Executable Files

CAB file extension

Windows Cabinet File

System Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DB file extension

Database File

Database Files

DLL file extension

Dynamic Link Library

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

JAR file extension

Java Archive File

Executable Files

MSI file extension

Windows Installer Package

Misc Files

NES file extension

Nintendo (NES) ROM File

Game Files

PDF file extension

Portable Document Format File

Layout Files

RTF file extension

Rich Text Format File

Text Files

TEX file extension

LaTeX Source Document

Text Files

XCODEPROJ file extension

Xcode Project

Developer Files