An amortization chart allows you to calculate what your monthly principle and interest payments should be. You must remember that in addition to your monthly P & I you will also have real estate taxes, home owners insurance, and quite possibly a HOA payment. The real estate taxes and home owners insurance are annual amounts, so take the dollar amount, let's say $600.00 per year for insurance and divide it by 12 months, so your monthly insurance amount is $50.00. Let's use real estate taxes of $1800.00 per year so divided by 12 months equals $150.00 per month for taxes. The last amount to consider is your HOA fee. When You add all these items up you end up with your total monthly payment.