The Stress Test: Why the Bank Tests You at ~7% When Current Rates Are Lower
A quick heads-up before we dive in: This article is strictly for general informational purposes and does not constitute financial, legal, or tax advice. Every situation is entirely unique, and bank lending policies and interest rates change frequently. Before making any decisions about your property journey, it is highly recommended that you seek independent advice from a qualified financial adviser.
When a New Zealand bank assesses your mortgage application, they do not calculate your borrowing power using the interest rate you see advertised on TV or the internet. Instead, they run your application through a "Servicing Test Rate."
Even if current 1-year fixed rates are sitting in the mid-4% to 5% range, the bank will calculate your ability to repay the loan at a significantly higher rate—currently hovering around 7% for most major lenders.
If you cannot afford the fictional repayments at that higher test rate, your mortgage application can be declined. It can feel incredibly frustrating to be rejected based on a rate you won't actually be paying, so here is a straightforward, jargon-free look at why banks use the stress test, and the hidden catch regarding how they calculate your everyday expenses.
Why Do Banks Use Such High Test Rates?
It is easy to look at a 7% test rate and assume the bank is just being unnecessarily strict. However, lenders have three very specific, highly regulated reasons for testing your application with a heavy buffer.
1. The 30-Year Reality (Rates Fluctuate)
A mortgage is a 30-year commitment, but you only lock in your interest rate for a few years at a time. The bank knows that a low rate today does not guarantee a low rate in 2030 or 2035. Historically, interest rates move in cycles. By testing your income against a much higher rate, the bank is ensuring that if the global economy shifts and rates skyrocket in the future, you won't immediately face a financial crisis when it comes time to refix.
2. The Responsible Lending Code (CCCFA)
New Zealand banks operate under strict government legislation, primarily the Credit Contracts and Consumer Finance Act (CCCFA). Under the responsible lending code, banks are legally obligated to ensure they do not lend you money that will put you into financial hardship. If a bank lent you money based purely on today's low rates without a buffer, and rates subsequently went up, the bank could be heavily penalized by regulators for irresponsible lending.
3. The "Life Happens" Buffer
The stress test isn't just about interest rates; it acts as an overarching safety buffer for your life. When the bank tests your maximum lending capacity at a higher rate, they are artificially inflating your expenses to see how much spare cash you have left over. That spare cash proves you can absorb unexpected life shocks—whether that is a sudden jump in property rates, a massive car repair bill, or having to go on a single income for a few months.
The Less Talked About Truth: Expenses Often Matter More Than the Test Rate
It is easy to get hung up on the test rate, but the reality is that the interest rate the bank uses is often less important than how they calculate your everyday living expenses.
Under current lending regulations, banks have to be incredibly thorough when deciding what it costs you to simply live your life. They apply strict formulas to find your borrowing capacity limits, and the catch is that different banks treat specific lifestyle expenses very differently.
A lower test rate won't help you if a bank's expense calculator aggressively wipes out your spare cash. Here is exactly what they are looking at:
Childcare Costs: The "Double-Dip" Effect Some banks calculate your childcare expenses as a completely separate, additional cost on top of your baseline expenses, while others are more pragmatic.
For example, imagine a single borrower who actually spends $1,000 per month on basic living expenses, plus $2,000 per month on childcare. Both Bank A and Bank B have an internal rule that a single borrower with one child must spend a minimum of $1,500 per month on basic living expenses—even though this specific borrower is more frugal.
Bank A (The Strict Approach): Takes their internal $1,500 minimum benchmark, stacks the $2,000 childcare cost on top of it, and calculates total expenses at $3,500.
Bank B (The More Realistic Approach): Takes the client's actual $1,000 basic expenses, adds the $2,000 childcare cost, and calculates total expenses at $3,000.
That $500 monthly difference can drastically change how much you are approved to borrow.
Insurance Premiums High monthly premiums for life, health, or income protection insurance can quickly drain the "spare cash" the bank thinks you have, significantly lowering your maximum lending capacity. Just like the childcare example above, some banks assume insurance is a strict extra cost to stack on top of your profile, while others view it as already built into your regular household outgoings.
KiwiSaver Outgoings If you generously contribute 8% or 10% to your KiwiSaver, nearly all banks will accept that you might lower your contribution back to the 3.5% minimum. Some might even allow you to suspend your contributions altogether to afford your mortgage, but this is not a decision to be taken lightly.
Varying Baseline Expenses Every bank assumes different families spend different amounts just to keep the lights on. Bank A might assume a couple with one child spends a minimum of $1,200 per month on life expenses (food, clothing, internet, power), while Bank B might deem $1,800 per month to be more appropriate. Even if you spend less than this in reality, the bank will override your actuals and use their built-in minimum figure. If you are a single borrower or have a high number of children, the difference between how banks assess your base expenses can vary wildly and make or break your application.
How Much Do Your Expenses Impact Your Loan?
See how the exact same single parent with one child—and comprehensive insurance—is assessed differently by three different lenders.
*Estimated borrowing capacity assumes a $120,000 gross salary, a ~7% servicing test rate, and standard uncommitted income buffers. For illustrative and educational purposes only.
How Home Loan Factory Can Help
When you walk into a single bank branch, you are entirely at the mercy of their specific, internal stress test and their unique rules for calculating your everyday expenses. If their expense benchmarks are harsh regarding your childcare or KiwiSaver contributions, you will get less money.
At Home Loan Factory, we have access to the exact, unadvertised servicing test rates and expense calculators of all the major lenders. Before we even submit your application, we run your numbers through the unique calculators of multiple different banks. We strategically match your specific lifestyle profile to the lender who will view your expenses the most favorably, ensuring you get access to the absolute maximum borrowing power your financial position allows.
To test out your borrowing capacity for yourself, try our Borrowing Power Calculator for a quick, indicative estimate.
Want to know exactly what you can actually borrow? Get in touch with the team at Home Loan Factory today for a clear, easygoing chat.
