Basic loan payment calculators are just one of the items that can help you get a feel for a potential real estate transaction. You can use my mortgage calculator that help you determine your payment amounts on a home.
An online mortgage calculator will offer you the ability to analyze slightly different twists to the payment scenario such as price of your home, interest rates and length of mortgage. This will help put your best foot forward when meeting with a financial professional. While mortgage calculators may not be exact (due to current rates and your specific home buying scenario), they can give you general information before meeting with a lender.