This amortization calculator is a nice tool if you are trying to plan out your true monthly payment. Make sure you take into account your PMI, taxes, homeowners insurance, association dues, and other monthly costs. For the best results, also try to be realistic about the interest rate you will receive with the bank. As you will notice on the monthly amortization breakdown, you can see how much of your payment is going towards the interest on the loan and how much is going to the principal of the loan. In the beginning you will be paying a majority of the interest, but that will change over time.