Just a basic tool I use to calculate out the css necessary for dynamic font scaling within a range (a minimum and maximum font size).

1) You set a range for the browser size: i.e. 320px to 1000px
2) and define the smallest and largest font sizes (i.e. what font size at 320px, and what at 1000px)
3) The result is a font that will scale smoothly between the two font sizes while the browser is scaled. hitting a min and max limit to avoid a font getting too large, or too small.

Below is the needed css, just paste this in the stylesheet, and enjoy your dynamic scaling font size for responsive designs.