Starbuck's or Not?
The Effects of Paying an extra \$100 a month on the Mortgage

by Ruth M. Naugle

What difference would it make to skip the morning coffee and add the money to the monthly mortgage payment?  A cup of coffee is not that expensive, but the money adds up over time.  Let's say that one bought a \$3.00 cup of coffee every morning.  Over a month, this would be approxiamately \$100.00.  Let's see the effects of adding this money to the mortgage payment.

The Mortgage Payment
Bob  is obtaining a loan for \$100,000.  The bank suggests that Bob apply for a 30-year fixed mortgage since the interest rates are down to 6.5%.  To determine the monthly payment, the following formula is used.

M=(Pr(1+r)^n)/((1+r)^n-1)

where
M = monthly payment
r  =  monthly interest rate
(.065/12)
n = number of payments
(12 months for the next 30 years)
12*30 = 360
P = Principal
(\$100,000)

Using the formula Bob determines his monthly payments will be \$632.08, not including escrow.  Wow, that's less than he is paying for rent!

As Bob is planning for his loan, he thinks of the cost of the loan over the next 30 years. Bob pays 632.08 each month for the next 30 years, then he will pay a total of \$227,548.80.  To find the amount he will pay in interest, he will subtracts the principal from the total paid.
\$227,548.80 - \$100,000  = 127,548.80
Over \$120,000 in interest seems like a lot of money to just pay the bank.

This has Bob thinking of ways to reduce the amount of interest he pays.  There are several ways to reduce the interest.  First, one can make a larger down payment to decrease the principal.  Second, one can try to obtain a lower interest rate.  Third, one can pay additional money each month towards the principal.  Since Bob does not have additional money for a down payment and 6.5% is already a low interest rate, Bob looks into putting additional money towards the principal.  Skipping the morning coffee would save @\$3.00 a day over @30 days a month, or about \$100.00 a month.  What effect would it have on the loan if this money was paid toward the principal of the loan each month?

Bob calculates his new mortgage payment will be \$732.08, with \$100.00 going towards the principal.  This loan will not take 30 years to pay off, but only 21 years!  The total amount paid is \$182,502.77.  Subtracting the principal from the total paid, he determines he will pay \$82,502.77 in interest.  Although that still seems like a lot of money, that is \$45,032.78 less than paying off the loan in 30 years.