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

TTF file extension

TrueType Font

Font Files

ZIP file extension

Zipped File

Compressed Files

PNG file extension

Portable Network Graphic

Raster Image Files

KMZ file extension

Google Earth Placemark File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

PCT file extension

Picture File

Layout Files

DRV file extension

Device Driver

System Files

RSS file extension

Rich Site Summary

Web Files

AIF file extension

Audio Interchange File Format

Audio Files

CSR file extension

Certificate Signing Request File

Web Files

CSV file extension

Comma Separated Values File

Data Files

CPL file extension

Windows Control Panel Item

System Files

DB file extension

Database File

Database Files

ZIPX file extension

Extended Zip File

Compressed Files

ASX file extension

Microsoft ASF Redirector File

Video Files