For anybody tired of using the clunky websites to calculate new versus old tire sizes, widths, and heights, I found this handy Excel Spreadsheet. The grey boxes are all drop downs. It allows you to compare two new tire/wheel combinations to an existing setup and shows what the differences will be in inches for height/diameter/radius. The difference for the backside and frontside of the new wheels is in millimeters and inches +/-.
https://www.dropbox.com/s/76fr1golryz6wtt/Tire-Wheel%20Calculator.xls?dl=0