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

PY file extension

Python Script

Developer Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

CPL file extension

Windows Control Panel Item

System Files

BAK file extension

Backup File

Backup Files

CFG file extension

Configuration File

Settings Files

CSV file extension

Comma Separated Values File

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

PIF file extension

Program Information File

Executable Files

MSI file extension

Windows Installer Package

Misc Files

LOG file extension

Log File

Text Files

PPS file extension

PowerPoint Slide Show

Data Files

CSS file extension

Cascading Style Sheet

Web Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

7Z file extension

7-Zip Compressed File

Compressed Files