On the Internet, Grid System was popularized by Nathan Smith, creator of the 960 Grid System, aka 960.gs—the most popular Grid System framework for building websites and rapid prototyping. You should use it every time you need to organize your content to build a website or when you need to build a rapid prototyping.
The modern grid, as we know today, was born after World War II, when some graphic designers began to devise a flexible system that would be able to help designers achieve coherency in organizing the page. Propagated mainly by Josef Muller-Brockmann in his book Grid Systems in Graphic Design, it is not hard to see the grids that have been used in the most popular websites on the Internet beyond print media.
One of the toughest decisions to make when you start with 960.gs is the number of columns you should use. The framework provides us with two variants: 12 or 16 columns.
The easiest way to decide which one to use is by asking the following question:
"Should my layout be divided by three?" If so, use 12 columns.
Don't worry if you didn't understand something. Sometimes, demonstrating is easier than explaining, and if you are like me, Grid System will be your best friend forever.