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

AVI file extension

Audio Video Interleave File

Video Files

BAK file extension

Backup File

Backup Files

C file extension

C/C++ Source Code File

Developer Files

CFG file extension

Configuration File

Settings Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

FLA file extension

Adobe Flash Animation

Developer Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

KMZ file extension

Google Earth Placemark File

GIS Files

LNK file extension

Windows File Shortcut

System Files

MDB file extension

Microsoft Access Database

Database Files

MP4 file extension

MPEG-4 Video File

Video Files

MSI file extension

Windows Installer Package

Misc Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WMV file extension

Windows Media Video File

Video Files