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

UUE file extension

Uuencoded File

Encoded Files

SLN file extension

Visual Studio Solution File

Developer Files

ZIPX file extension

Extended Zip File

Compressed Files

KEY file extension

Keynote Presentation

Data Files

LNK file extension

Windows File Shortcut

System Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

AZW file extension

Amazon Kindle eBook File

eBook Files

7Z file extension

7-Zip Compressed File

Compressed Files

VCF file extension

vCard File

Data Files

VCD file extension

Virtual CD

Disk Image Files

CGI file extension

Common Gateway Interface Script

Executable Files

ICS file extension

iCalendar File

Misc Files