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

AIF file extension

Audio Interchange File Format

Audio Files

PY file extension

Python Script

Developer Files

CLASS file extension

Java Class File

Developer Files

BIN file extension

Binary Disc Image

Disk Image Files

IFF file extension

Interchange File Format

Audio Files

HTML file extension

Hypertext Markup Language File

Web Files

SH file extension

Bash Shell Script

Developer Files

APP file extension

Mac OS X Application

Executable Files

GZ file extension

Gnu Zipped Archive

Compressed Files

COM file extension

DOS Command File

Executable Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

CSV file extension

Comma Separated Values File

Data Files

KML file extension

Keyhole Markup Language File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

RTF file extension

Rich Text Format File

Text Files