Yes, the default font size changes form one browser to another. And then even if we use the same browser, I can set the font sizes to whatever I want on my browser. Don't assume anything. If you want the font to be 18px hight then you must tell it to be 18px high. Don't assume that just cause your version of IE displayed it at 18px by default that the rest of the world will see it exactly the same as you did.