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

FNT file extension

Windows Font File

Font Files

7Z file extension

7-Zip Compressed File

Compressed Files

3DS file extension

3D Studio Scene

3D Image Files

MSI file extension

Windows Installer Package

Misc Files

CRX file extension

Chrome Extension

Plugin Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

GBR file extension

Gerber File

Data Files

MSG file extension

Outlook Mail Message

Text Files

MAX file extension

3ds Max Scene File

3D Image Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

PART file extension

Partially Downloaded File

Misc Files

PHP file extension

PHP Source Code File

Web Files

VCF file extension

vCard File

Data Files

DMG file extension

Mac OS X Disk Image

Disk Image Files