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

TOAST file extension

Toast Disc Image

Disk Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

BIN file extension

Binary Disc Image

Disk Image Files

BAT file extension

DOS Batch File

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

3GP file extension

3GPP Multimedia File

Video Files

DEB file extension

Debian Software Package

Compressed Files

DNG file extension

Digital Negative Image File

Camera Raw Files

IFF file extension

Interchange File Format

Audio Files

PPS file extension

PowerPoint Slide Show

Data Files

MID file extension

MIDI File

Audio Files

WPD file extension

WordPerfect Document

Text Files

RTF file extension

Rich Text Format File

Text Files

DLL file extension

Dynamic Link Library

System Files

GPX file extension

GPS Exchange File

GIS Files