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

KEY file extension

Keynote Presentation

Data Files

PS file extension

PostScript File

Vector Image Files

SLN file extension

Visual Studio Solution File

Developer Files

BAT file extension

DOS Batch File

Executable Files

DNG file extension

Digital Negative Image File

Camera Raw Files

AI file extension

Adobe Illustrator File

Vector Image Files

CER file extension

Internet Security Certificate

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

EPUB file extension

Open eBook File

eBook Files

COM file extension

DOS Command File

Executable Files

TOAST file extension

Toast Disc Image

Disk Image Files

CAB file extension

Windows Cabinet File

System Files

LNK file extension

Windows File Shortcut

System Files

PL file extension

Perl Script

Developer Files

VCF file extension

vCard File

Data Files