Starting with the first line of entry fields, enter each one of your debts, along with their corresponding principal balances, interest rates and monthly payment amounts (the last two columns will be filled in by the calculator). Once you have entered all of the debts you wish to consolidate, click on the "Compute Current Debt Cost" button. Next, enter the consolidating loan's interest rate, term and any origination fees that might apply and click the "Compute Consolidation Loan Costs" button.