When the borrowers go into the lender, the lender is supposed to give them under federal law a good save estimate of what their expenses for closing are going to be. At that time, they can also say "if you borrow this much money at this interest rate, your monthly principal and interest payment will be deducted out." Now generally speaking, most lenders want what they call a budget mortgage, otherwise known as PITI and that includes the principal and interest. But then depending on the taxes on the home and the insurance policy on the home the lender also wants to collect 1/12th of the annual taxes and the annual premium of the hazard insurance so that when those bills come due the lender can pay them. So that would change your monthly as well.
