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

AIF file extension

Audio Interchange File Format

Audio Files

APK file extension

Android Package File

Executable Files

CER file extension

Internet Security Certificate

Web Files

CGI file extension

Common Gateway Interface Script

Executable Files

CSS file extension

Cascading Style Sheet

Web Files

CUR file extension

Windows Cursor

System Files

DB file extension

Database File

Database Files

DBF file extension

Database File

Database Files

EXE file extension

Windows Executable File

Executable Files

HTM file extension

Hypertext Markup Language File

Web Files

PART file extension

Partially Downloaded File

Misc Files

PPS file extension

PowerPoint Slide Show

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

WMV file extension

Windows Media Video File

Video Files

WPD file extension

WordPerfect Document

Text Files