# Em Typography

Chris Messina links to this somewhat handy Em Calculator. It claims to make it easier to do pixel-perfect design without compromising accessibility. My understanding was that this is kind of innacurate. most browsers don’t render more than two decimal places worth of Em. Since I prefer to set the default at 10px (it makes the math easy), that means setting my em’s to $\frac{5}{8}$ (0.625) which most browser will truncate to 0.63. I’ve always (since reading it in Matthew Stephens‘ hilariously commented CSS) used the 76% method in my body, from sane CSS typography, and then used em’s to style the remaining elements.