Your mortgage is probably your biggest financial commitment. Here’s how to make it work harder for you.
Most people set up their mortgage and leave it on autopilot. It pays itself down over time, and when the fixed rate expires they refix and move on. That approach works — but it’s an expensive way to do it.
Small, deliberate changes to how you manage your home loan can save you tens of thousands of dollars in interest and take years off your mortgage term. And the faster you build equity, the sooner you’re in a position to buy an investment property.
Here are four strategies we use with clients at Finsol to do exactly that. We’ll use a $700,000 mortgage at 5.75% — a realistic average across the last decade — to show what the numbers look like in practice.
1. Switch to fortnightly repayments
This is one of the easiest changes you can make and costs nothing to set up. Most mortgages default to monthly repayments — but switching to fortnightly means you end up making 26 half-payments per year rather than 12 full ones. That’s the equivalent of one extra full monthly payment every year, applied directly to your principal.
On a $700,000 mortgage at 5.75%, that single change saves around $50,000 in interest and cuts roughly three years from your loan term. You barely notice the difference in your weekly cashflow, but the compounding effect over time is significant.
One thing to check: make sure your lender is calculating interest daily, not monthly. Most major New Zealand banks do, but it’s worth confirming — if interest is calculated monthly, the fortnightly frequency won’t deliver the same benefit.
2. Pay a little more each month
Your minimum repayment is calculated to clear the loan over 30 years — anything above that goes straight off the principal.
On a $700,000 mortgage at 5.75%, the minimum monthly repayment is around $4,086. Increase that by 10% — an extra $409 per month — and you’d save approximately $98,000 in interest over the life of the loan and cut around six years from your term.
The compounding effect is what makes this work. Less principal means less interest accrues, which means your additional payments have an accelerating impact over time.
One thing to check: if you’re on a fixed rate, your lender may cap how much extra you can pay without triggering a break fee. Most banks allow up to 5–10% of the balance per year. It’s worth confirming before you start — this is the kind of detail a good mortgage adviser will pick up for you.
3. Put your savings to work with an offset facility
An offset mortgage links your home loan to a savings or transaction account. The balance in that account is offset against your mortgage balance daily, so you only pay interest on the difference.
If you have a $700,000 mortgage and $30,000 sitting in an offset account, you’re paying interest on $670,000. At 5.75%, that saves around $1,725 per year — tax-free — and around $51,750 over the life of the loan if you maintain that balance.
The money stays accessible, which matters. Unlike making a lump sum payment, your offset savings aren’t locked away. That flexibility makes it particularly useful if you’re building towards a deposit on an investment property — the funds are working hard against your mortgage right up until the moment you need them.
Not all lenders offer offset facilities, and those that do structure them differently. Some attach the offset to a floating rate, which may be higher than a fixed rate. Getting the structure right is important — it’s not always as simple as it looks on a comparison website.
4. Use the refix moment to make a lump sum payment
When your fixed rate term expires, you have a window to make a lump sum payment against the principal before you refix. For most New Zealand borrowers refixing annually, this is the one time each year you can reduce the balance without risking break fees.
A $5,000 lump sum at each annual refix saves approximately $42,000 in interest over the life of a $700,000 mortgage and cuts three to four years from the term. The earlier in the loan you do it, the bigger the impact — because that $5,000 reduction lowers the base on which all future interest is calculated.
Most people treat the refix as a rate decision. It is — but it’s also the best time to review your full mortgage structure, consider whether to split between fixed and floating, and look at whether there’s cash available to reduce the principal. At Finsol, we build refix check-ins into our client calendar so that window doesn’t get missed.
What happens when you combine all four?
Each strategy works on its own. Used together, they compound each other. Fortnightly repayments and monthly overpayments chip away at the principal continuously. The offset facility reduces daily interest on whatever balance remains. The annual lump sum accelerates the reduction at each refix.
On a $700,000 mortgage at 5.75%, deploying all four strategies could reduce your total interest bill by well over $175,000 and take ten or more years off your mortgage term. The exact figures depend on your rate, lender, and structure — but the direction of travel is significant.
The link to the investment property
Equity is the asset that opens the door to an investment property — and you build it two ways at once. Your mortgage balance goes down as you pay it off, and your property value (in most markets, over time) goes up. Both movements work in your favour.
As a rough example: a home purchased at $875,000 with a $700,000 mortgage starts with $175,000 in equity. After five years of active debt reduction, the mortgage balance might be closer to $590,000. If the property has grown conservatively to $975,000, equity is now around $385,000 — more than double.
The question is usually about sequencing and structure — how to access that equity, how to set up the lending so it doesn’t tie your hands, and when the timing is right.
These are exactly the conversations we have with clients who are working towards their first investment property.
Talking to a mortgage adviser in New Zealand
Getting quality mortgage advice isn’t just about finding the lowest rate. It’s about structuring your lending in a way that actually serves your long-term goals — whether that’s paying off your home faster, building equity, or positioning yourself for investment property.
At Finsol, we work with clients across New Zealand, on exactly this kind of planning.
If you’d like to understand where you sit and what your options look like, we’re happy to have that conversation.
This article is for informational purposes only and should not be considered as financial advice. It is always recommended to consult with a qualified financial professional before making any financial decisions based on your individual circumstances.
