The maths behind your mortgage – how to save thousands

LATELY, HOMEOWNERS have been dreading announcements from the Reserve Bank’s Monetary Policy Committee.

Inflation has been running rampant due to the war in Ukraine and what we now call the post-covid-19 hangover. This has led to central banks hiking interest rates to combat the rising cost of living.

But what do all these technical terms mean for you, and how does it affect your pocket? The answer to this lies in understanding the math behind your mortgage.

The effect of a rate hike on your bond

The prime interest rate is the basic rate of interest that commercial banks charge their clients when lending them money. In 2020, at the height of the Covid-19 pandemic, the prime interest rate was 7%. At the time of writing, the prime interest rate is sitting at 9.75%.

While a difference of 2.75% might not seem like much, over time the difference is massive.

Let’s take an example. Sam finds her dream home, but, unfortunately, the price tag is R1 500 000. She contacts her bank for assistance.

Because Sam is such a loyal customer and has a good credit record, her bank offers to loan her the full

R1 500 000 at a rate equal to prime (7%) over a 30-year period (see table). This means that, over the 30 years, Sam will have paid almost R2 100 000 to her bank for lending her the money to buy her home.

Now assume the interest rate increases to 9.75%. Not only has Sam’s monthly repayment gone up by almost R3 000, she will have to pay an extra R1 046 520 to her bank over the 30-year term.

Paying an extra R100 a month Sam is shocked to see the numbers and has decided to add an extra R100 a month towards her bond.

By paying an extra R100 a month

on her bond, Sam reduces the repayment term by 15 months and saves R165 000 in interest (see table).

Paying an extra R500 a month With an extra R100 looking so good, Sam tries to cut back on daily expenses to scrape together a total of R500. The effect is astounding. Sam has now reduced the repayment term by 61 months – more than five years! She has also saved a whopping R649 000 in interest (see table).

The math is simple – the more you pay (either a month or by way of a lump sum), the more you will save.

More tips to save on your bond While the most obvious solution might be to pay extra towards your bond, this might not always be possible – especially with the tough economic conditions most South Africans are experiencing.

If you are not in a position to add extra funds to your bond, you can renegotiate the interest on your existing home loan.

This can be done directly with the bank that provided you with the loan in the first place.

You can also consider approaching a bond originator who will approach the different banks on your behalf and provide you with the best possible offer.

If interest rates rise further and you find yourself struggling to meet your bond repayments, here are a few things you can consider:

● Rent out a portion of your property as an Airbnb or an office.

● Rent your garage to neighbours who need extra space.

● Consider a house-share arrangement for short-term rental income.

● Start working your passion into a second stream of income. For example, if you love photography, offer your services for weddings or children’s parties.

● If all else fails, consider moving to a more affordable property

● Becoming financially independent is the culmination of many small changes in your behaviour and your approach to money.

● Consider approaching a Certified Financial Planner (CFP) to better understand the options available to you and how they can change your life for the better.