Mortgage Payment Reduction Versus Rate Reduction
July 24, 2000
“A lender in our area is promoting a biweekly payment program by
claiming that the reduction in interest payments under the program is
the equivalent of a reduction in interest rate. Can this be right?”
Lenders promoting biweekly payment plans often blur the distinction
between interest payments and the interest rate.
Suppose you currently spend $24 a month to buy 12 pounds of flour at $2
a pound. Your spending could be reduced to $12 a month if you purchased
only 6 pounds, or if the price was reduced to $1 a pound.
If someone told you that these were equivalent ways to reduce your flour
spending, you’d pass it off as nonsense. But when exactly the same
argument is made regarding mortgages, you aren’t so sure. And judging
from my mail, your confusion is widely shared.
The interest rate on a mortgage is the price of money, which is
analogous to the price of flour. The interest payment is the rate times
the amount borrowed, just as spending on flour is the price of flour
times the amount purchased.
What makes the mortgage (or any financial claim) a little different is
that the “amount” has two dimensions: the initial loan amount and how
long you have it. But this does not affect the basic principle that was
so obvious in the case of flour: Reducing interest payments by reducing
the amount borrowed is very different from reducing interest payments by
reducing the interest rate. Here are some illustrations.
Case 1: You borrow $200 for two months at 1% a month. At the end of
month 1, you pay $2 interest. The interest payment is calculated by
multiplying the interest rate times the loan balance -- .01 times $200 =
$2. At the end of month 2, you again pay $2 interest, along with the
loan balance of $200. Total interest payments on this loan are $4.
Case 2: Reduce the loan amount to $100. The interest payment is now .01
times $100 = $1 for month one, and another $1 for month 2, for a total
of $2.
Case 3: Shorten the same $100 loan to one month. At the end of the
month, you pay $101, with interest payments of $1.
Case 4: Reduce the interest rate on the $100 loan to 0.5% a month. At
the end of the month, you pay $100.50, with an interest payment of $.50
In Case 2 the interest payment is reduced by taking a smaller loan, in
Case 3 by borrowing for a shorter period, and in Case 4 by paying a
lower interest rate. But only case 4 provides a clear benefit to the
borrower. In the other two cases, the borrower pays less because he
receives less.
The amount borrowed on a mortgage depends on the initial loan amount,
and on how long you have it, which in turn depends on how rapidly you
repay it. Thirty-year mortgages that convert to a biweekly payment plan
add an extra monthly payment each year. This pays off the loan more
quickly, reducing total interest payments. Lenders typically charge for
conversion to a biweekly.
There is nothing wrong with a biweekly plan, if you understand what you
get for your money. Your interest payments decline because you reduce
the amount borrowed, but that’s not equivalent to reducing the rate.
Furthermore, if you want to reduce the amount borrowed by paying off
early, you can do it without the cost of setting up a biweekly plan.
Just add to your regular monthly payment an amount equal to 1/12 of the
payment.
Consider a biweekly plan if you want to pay off your loan faster but
don’t have the discipline. A biweekly provides the discipline, and that
is all it provides.