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

FON file extension

Generic Font File

Font Files

DAT file extension

Data File

Data Files

MSG file extension

Outlook Mail Message

Text Files

ZIP file extension

Zipped File

Compressed Files

KEY file extension

Keynote Presentation

Data Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

M file extension

Objective-C Implementation File

Developer Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

FNT file extension

Windows Font File

Font Files

PCT file extension

Picture File

Layout Files

DXF file extension

Drawing Exchange Format File

CAD Files

7Z file extension

7-Zip Compressed File

Compressed Files

DNG file extension

Digital Negative Image File

Camera Raw Files

MP4 file extension

MPEG-4 Video File

Video Files

IFF file extension

Interchange File Format

Audio Files