Should I set the default font-size on the body or html element?

Question

I like to work in ems when creating websites. Therefore I set a default font-size of 100.01% on the body element.

My question is should I set the default font-size on the body or the html element? What are the pros and cons (if any) of both?

Answer 1

Now that the rem unit is starting to become popular, setting the base font-size on the root element (html tag) is advised (rem stands for root em).

Answer 2

I don't believe there is any advantage or disadvantage to setting the base font-size on either html or body to allow for sizing with ems; they will both have the same effect.

Not related to the question:

I would however suggest using a different default font-size. I would set it as:

body {     font-size: 62.5%; } 

Doing this reduces the default font-size from 16px down to 10px. This then makes choosing font-size much easier as there is no need for difficult calculations. It means that 1em is equal to 10px and so calculating the px size is a matter of multiplying by 10:

• 1.0em = 10px
• 1.4em = 14px
• 1.8em = 18px
• 2.2em = 22px