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

CLASS file extension

Java Class File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CS file extension

Visual C# Source Code File

Developer Files

DB file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

FON file extension

Generic Font File

Font Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

ICS file extension

iCalendar File

Misc Files

KMZ file extension

Google Earth Placemark File

GIS Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files

TXT file extension

Plain Text File

Text Files

WAV file extension

WAVE Audio File

Audio Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

ZIP file extension

Zipped File

Compressed Files