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

CRX file extension

Chrome Extension

Plugin Files

DB file extension

Database File

Database Files

DOC file extension

Microsoft Word Document

Text Files

DOC# file extension

Microsoft Word Document

Text Files

FLA file extension

Adobe Flash Animation

Developer Files

HTML file extension

Hypertext Markup Language File

Web Files

MID file extension

MIDI File

Audio Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PRF file extension

Outlook Profile File

Settings Files

RTF file extension

Rich Text Format File

Text Files

SQL file extension

Structured Query Language Data File

Database Files

UUE file extension

Uuencoded File

Encoded Files

WMV file extension

Windows Media Video File

Video Files

3G2 file extension

3GPP2 Multimedia File

Video Files