Repaying A Mortgage

Mortgage payments consist of two parts: payments for interest and for principal. Interest is the fee for using the lender's money. Principal is the amount of the loan still owed. A portion of each payment pays interest and the remaining portion reduces the principal. The process of paying off the principal while paying interest is called amortization.

When a homeowner begins to repay his or her mortgage almost all of each monthly payment pays for interest. This changes as the loan ages, even though the amount paid each month may not change. Each month's payment reduces the principal by a small amount, therefore less interest is owed the next month. Since less interest is owed, more of the payment can be used to reduce the principal. Gradually less of each month's payment is needed to pay interest, and more goes to reduce the principal.

For example, if a person borrows $80,000 at 8.0 percent for 20 years to buy a home, he or she will make monthly payments of about $669.15. Out of the first month's payment, about $533.33 pays interest on the principal ($80,000 × 8 percent interest per year ÷ 12 months per year = $533.33). The balance of the monthly payment, $135.82, reduces the principal. The second month's payment is based on the new principal of $79,864.18. This time, $532.43 goes toward interest ($79,864.18 × 8 percent ÷ 12 months) and $136.72 reduces the principal. The relationship between the amount of each monthly payment that goes to interest and principal changes over time. The first 13 years of a 20-year mortgage—or about two-thirds its life—pays back half the principal. During the last seven years, more and more of the monthly payment goes to reduce the principal until the debt is completely paid. At the end of the 20-year, $80,000 mortgage, the borrower will have made 240 monthly payments totaling about $160,500.