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CSS CSS Foundations Text, Fonts, and Lists Font Properties

Zach Saul
Zach Saul
11,156 Points
Posted by Zach Saul
Zach Saul
11,156 Points

Practical difference between specifying font size with "em" units or percentages?

What is the difference (if there is one) between using "em" units to specify font size and using percentages?

it's my understanding both are relative to the font size of their parent element, and both use a version of percentages (2 em = 200%) as they reference the same thing.

I am essentially asking if these two pieces of code are at all different:

p { font-size: 2em; }

OR

p { font-size: 200%; }

are there in situations where i should use one as opposed to the other??

1 Answer

Ivan Burda
Ivan Burda
10,897 Points
Ivan Burda
Ivan Burda
10,897 Points

I have tried to find out an answer to your question because I would like to know it too. The outcome of my efforts is that both "em" and "%" are relatively safe and mutually replaceable. Some problems may arise when the browser allows you to change the default font size. Check the two articles below for more information. I would not be worried too much about using any of the two units, however, I would be very careful with absolute unitss such as pixels, dots, etc.

1) http://stackoverflow.com/questions/132685/font-size-in-css-or-em 2)http://kyleschaeffer.com/development/css-font-size-em-vs-px-vs-pt-vs/ (this articles is not very recent though)