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

ACCDB file extension

Access 2007 Database File

Database Files

AIF file extension

Audio Interchange File Format

Audio Files

APP file extension

Mac OS X Application

Executable Files

AVI file extension

Audio Video Interleave File

Video Files

COM file extension

DOS Command File

Executable Files

CUR file extension

Windows Cursor

System Files

DBF file extension

Database File

Database Files

GED file extension

GEDCOM Genealogy Data File

Data Files

MID file extension

MIDI File

Audio Files

OTF file extension

OpenType Font

Font Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

RSS file extension

Rich Site Summary

Web Files

VB file extension

VBScript File

Executable Files

VCF file extension

vCard File

Data Files

3GP file extension

3GPP Multimedia File

Video Files