Like HowStuffWorks on Facebook!

How Mortgages Work

The Mortgage Payment

The down payment on a mortgage is the lump sum you pay upfront that reduces the amount of money you have to borrow. You can put as much money down as you want. The traditional amount is 20 percent of the purchasing price, but it's possible to find mortgages that require as little as 3 to 5 percent. The more money you put down, though, the less you have to finance -- and the lower your monthly payment will be.

The monthly mortgage payment is composed of the following costs, appropriately known by the acronym PITI:

  • Principal - The total amount of money you are borrowing from the lender (after your down payment)
  • Interest - The money the lender charges you for the loan. It's a percentage of the total amount of money you're borrowing.
  • Taxes - Money to pay your property taxes is often put into an escrow account, a third-party entity that holds accumulated property taxes until they're due.
  • Insurance - Most mortgages require the purchase of hazard insurance to protect against losses from fire, storms, theft, floods and other potential catastrophes. If you own less than 20 percent of the equity in your home, you may also have to buy private mortgage insurance, which we'll talk more about later.

With a fixed-rate mortgage, your monthly payment remains roughly the same for the life of the loan. What changes from month to month and year to year is the portion of the mortgage payment that pays down the principal of the loan and the portion that is pure interest. The gradual repayment of both the original loan and the accumulated interest is called amortization.

If you look at the amortization schedule for a typical 30-year mortgage, the borrower pays much more interest than principal in the early years of the loan. For example, a $100,000 loan with a 6 percent interest rate carries a monthly mortgage payment of $599. During the first year of mortgage payments, roughly $500 each month goes to paying off the interest; only $99 chips away at the principal. Not until year 18 does the principal payment exceed the interest.

The advantage of amortization is that you can slowly pay back the interest on the loan, rather than paying one huge balloon payment at the end. The downside of spreading the payments over 30 years is that you end up paying $215,838 for that original $100,000 loan. Also, it takes you longer to build up equity in the home, since you pay back so little principal for so long. Equity is the value of your home minus your remaining principal balance.

But that doesn't mean that fixed-rate, 30-year mortgages are a bad thing. Far from it. We'll look closer at fixed-rate mortgages on the next page.