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

ASF file extension

Advanced Systems Format File

Video Files

BIN file extension

Binary Disc Image

Disk Image Files

C file extension

C/C++ Source Code File

Developer Files

GED file extension

GEDCOM Genealogy Data File

Data Files

INI file extension

Windows Initialization File

Settings Files

MDB file extension

Microsoft Access Database

Database Files

MOV file extension

Apple QuickTime Movie

Video Files

MP3 file extension

MP3 Audio File

Audio Files

MP4 file extension

MPEG-4 Video File

Video Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PRF file extension

Outlook Profile File

Settings Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

SAV file extension

Saved Game

Game Files

TIF file extension

Tagged Image File

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files