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

DDS file extension

DirectDraw Surface

Raster Image Files

CSS file extension

Cascading Style Sheet

Web Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

CGI file extension

Common Gateway Interface Script

Executable Files

DRV file extension

Device Driver

System Files

INI file extension

Windows Initialization File

Settings Files

MPA file extension

MPEG-2 Audio File

Audio Files

TARGZ file extension

Compressed Tarball File

Compressed Files

ASF file extension

Advanced Systems Format File

Video Files

MSG file extension

Outlook Mail Message

Text Files

EXE file extension

Windows Executable File

Executable Files

JAVA file extension

Java Source Code File

Developer Files

YUV file extension

YUV Encoded Image File

Raster Image Files

CSV file extension

Comma Separated Values File

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files