Font Sizes on the Web
Most Windows fonts include a wide range of built-in sizes, typically ranging from 8 to 72 points. TrellixWeb, the software used to create this site, can display all the built-in sizes of any font that is installed in the computer.

Many software programs have features that allow them to display or print additional sizes, either larger or smaller than the sizes built into the font, or even in between them. In Microsoft Word, for example, you can easily display and print 13.5 point Arial, or 128 point Times New Roman, even though those sizes are not built into the Arial or Times New Roman fonts.

On the web, the situation is completely different. Most browsers can display only seven different sizes for any font. Instead of using point size to describe the size of a character, the browser uses a number from 1 to 7. So whenever a font size is specified in points, either your browser or your web authoring software automatically converts it to a size from 1 to 7.

You can see that process in action by using your browser to display any font in the samples on this site. Each sample was created using 16 different sizes, from 8 to 72 points. But when your browser displays the sample, it shows only seven different physical sizes.

Point Size
Web Size
8, 9
1
10, 11
2
12
3
14, 16
4
18, 20, 22
5
24, 26, 28
6
36, 48,72
7
Internet Explorer maps the sizes according to the table to the right. Other browsers may use a different system.

If you are using Internet Explorer to display the samples on this site, the 8 point and 9 point samples will appear in the same size on the screen, even though they are different in the underlying document. The same is true of the 10 point and 11 point samples, and of the others listed in the table.

The reason for all this is simple, once you understand it. While word processors and other programs are designed for precise formatting of pages created by a single author, web browsers are designed to display readable text on a wide variety of computers and monitors, from material prepared by anyone who puts anything up onto the web. To achieve their goal, browsers dispense with the precision that is so much more important elsewhere.