For those of you who are still using pixels, it’s about time you made the switch to ems or points. It allows users who have a hard time reading small type to enlarge the font. Here is a little trick that will help you so you don’t have to remember the chart above.
body { font-size: 62.5% }
This will make 1.0 em the same as 10px. So if you wanted 12 px. would be 1.2em, nice and easy. Hopefully this will help you out, I know I use it all the time. Enjoy.