The first calculator is designed to compare a fixed rate and a variable rate over a 5 year term. You have the option to predict rate changes throughout the term of the variable rate mortgage and it will give you the equivalent fixed rate with these changes. It will also tell you which mortgage allows you to come out ahead and by how much.
In order to make this an accurate comparison the monthly payment will be the same for both rates, based on the fixed rate. This eliminates any time value of money issues.