Question - Loan Amortization. Bankrate, has a financial calculator that will prepare an amortization table based on your inputs. First, find the APR quoted on the website for a 30-year fixed rate mortgage. You want to buy a home for $200,000 on a 30-year mortgage with monthly payments at the rate quoted on the site. What percentage of your first month's payment is principal? What percentage of your last month's payment is principal? What is the total interest paid on the loan?