In the widest definition possible, amortization (pronounced: am-ohr-tih-ZAY-shun) is the scheduled process by which a loan’s principal balance pays down to $0.
The opposite of an amortizing loan is an interest only loan for which there is no scheduled principal repayment schedule.
With respect to mortgages, amortization is what determines how much of a monthly payment goes to principal, and how much goes to interest. Amortization schedules are the same for all fixed rate, non-interest only home loans including 15- and 30-year fixed rate mortgages, as well as all non-interest only ARMs.
Monthly principal and interest payments on a mortgage are based on the mathematical formula above, where:
- P = principal
- A = payment
- r = monthly interest rate
- n = number of payments
Now, if you’ve ever paid on an amortizing home loan, you don’t need to use the formula to know that mortgage amortization schedules are dramatically front-loaded with interest.
In other words, in the early years of loan, the interest due on a mortgage is relatively high versus the principal due. And, if you’ve ever heard someone say, “You don’t pay down much of a loan in the first few years,” now you know — mathematically — why that is.
This interest-heavy mortgage repayment schedule helps banks to collect as much loan interest as possible up-front, offsetting potential loan losses.
But, just because the bank sets an amortization schedule doesn’t mean that a homeowner can’t change it. In any given month, a borrower can prepay extra principal to the lender, thereby changing the formula and accelerated the loan payoff date.
There are calculators online that do the prepayment math for you, but before making extra payments, talk with your loan officer or financial advisor first. Prepaying your mortgage could trigger a stiff penalty from your lender, or put your liquid assets at risk. Prepayment is not a bad plan, but it may be a bad plan for some.