Amount

• According to the U.S. Census Bureau, the average price for a new home sold in the United States in 2009 was $270,900. But that's not the amount you'll borrow. You usually pay some money up front---a down payment. You may have $100,000 to use for a down payment, so your mortgage payment will be based on borrowing $170,900. You may only have $40,000, in which case your mortgage payment will be based on borrowing $230,900. You will also have costs related to purchasing the house and borrowing the mortgage money that will affect your monthly payments.
  
  

Rate

• Your mortgage payment depends on the interest rate and the length of mortgage you choose. You can get a temporary low-interest rate for a short period---an adjustable-rate mortgage or a balloon mortgage. You can also opt for a slightly higher permanent rate for the duration of your mortgage---a fixed-rate mortgage.
  
  

Payments

• Most banks and financial institutions offer a mortgage calculator. You enter the amount you will borrow and select the mortgage length; the calculator will figure out your monthly payment. If you borrow the full amount for a mortgage on a $270,900 home, at a fixed rate of 4.25 percent for 30 years, your monthly payment will be $1,333.