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

ASP file extension

Active Server Page

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

C file extension

C/C++ Source Code File

Developer Files

CSS file extension

Cascading Style Sheet

Web Files

CUE file extension

Cue Sheet File

Disk Image Files

CUR file extension

Windows Cursor

System Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

GED file extension

GEDCOM Genealogy Data File

Data Files

ICS file extension

iCalendar File

Misc Files

ISO file extension

Disc Image File

Disk Image Files

JPG file extension

JPEG Image

Raster Image Files

LOG file extension

Log File

Text Files

TMP file extension

Temporary File

Backup Files

WPD file extension

WordPerfect Document

Text Files