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

AI file extension

Adobe Illustrator File

Vector Image Files

C file extension

C/C++ Source Code File

Developer Files

CAB file extension

Windows Cabinet File

System Files

DBF file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

DTD file extension

Document Type Definition File

Developer Files

GAM file extension

Saved Game File

Game Files

JAR file extension

Java Archive File

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

TTF file extension

TrueType Font

Font Files

WPD file extension

WordPerfect Document

Text Files

ZIPX file extension

Extended Zip File

Compressed Files