5% and a term of 30 years. You're not in fact paying just 4. 5% of $200,000 as interest; you're paying interest on what stays of the balance after each payment every month. Since your regular monthly payment is only a small portion of the overall quantity you owe, only a tiny part of the loan balance makes money off, and interest gets charged again on that balance the next month.Your mortgage payment is the very same every month unless your rate of interest changes, but the parts of your mortgage payment that goes towards your principal and interest charges changes the longer you have the home loan. Interest payments are front-loaded early on and are slowly decreased till principal payments begin to surpass them.