NZ Mortgage Stress Test Calculator
Calculate whether your income passes the New Zealand bank mortgage servicing test. Enter your loan amount and income to see your stress-tested payment, compare RBNZ-guided servicing rates across ANZ, ASB, BNZ, Westpac, and Kiwibank, model the impact of RBNZ DTI caps, and explore strategies including parental guarantors and larger deposits. All figures in NZD.
Each NZ bank sets its own servicing test rate, which is the rate used to calculate your stress-tested payment. These rates are typically 2-3% above current market rates and change periodically. Rates shown are approximate 2024-25 values.
| Bank | Approx. Servicing Rate | Monthly Payment (Stress) | Total Monthly Commitments | Can You Qualify? |
|---|---|---|---|---|
| ANZ | 8.65% | NZ$4,677 | NZ$6,877 | No |
| ASB | 8.65% | NZ$4,677 | NZ$6,877 | No |
| BNZ | 8.60% | NZ$4,656 | NZ$6,856 | No |
| Westpac | 8.65% | NZ$4,677 | NZ$6,877 | No |
| Kiwibank | 8.60% | NZ$4,656 | NZ$6,856 | No |
RBNZ introduced Debt-to-Income (DTI) ratio restrictions in mid-2024. Owner-occupiers are limited to borrowing a maximum of 6x gross income; investors 7x gross income. These caps operate alongside (not instead of) the servicing test.
How to Use the NZ Mortgage Stress Test Calculator
Enter your loan amount, contract rate, stress buffer (typically 2-3%), gross annual income, and existing monthly debts. The calculator applies the bank servicing test and shows whether your income qualifies for the loan, your stress-tested monthly payment, and the qualifying income required.
What Is the NZ Mortgage Stress Test?
- Servicing test: NZ banks calculate your ability to service a loan at a rate significantly higher than the current market rate — typically 2-3% above your contract rate
- RBNZ requirement: The Reserve Bank of New Zealand requires banks to test borrowers' ability to repay at higher rates as a financial stability measure
- Living costs: Banks deduct estimated household living costs (UCCS) from your income before assessing capacity
- DTI caps: Since mid-2024, RBNZ also applies Debt-to-Income ratio speed limits — 6x income for owner-occupiers, 7x for investors
- Each bank differs: Individual banks set their own servicing test rates, which vary slightly and change over time
Formula: NZ Bank Servicing Test
Stress Payment = Loan Amount × [r(1+r)&sup n;] ÷ [(1+r)&sup n; − 1]
where r = Stress Rate ÷ 12, n = months
Total Monthly Commitments = Stress Payment + Existing Debts + UCCS Living Costs
Qualifying Income = Total Monthly Commitments ÷ Max DTI Ratio
Example ($600,000 loan, 6.89% contract rate, 2% buffer, 30 years):
Stress Rate = 6.89% + 2.00% = 8.89%
Stress Payment = $4,739/mo
UCCS (2-person household) = $1,700/mo
Existing Debts = $500/mo
Total Commitments = $6,939/mo
Qualifying Monthly Income (at 45% DTI) = $6,939 ÷ 45% = $15,420/mo
Qualifying Annual Income = $185,040
NZ Bank Servicing Rates (Approximate 2024-25)
| Bank | Approx. Servicing Rate | Notes |
|---|---|---|
| ANZ | ~8.65% | Subject to change; confirm with bank |
| ASB | ~8.65% | Subject to change; confirm with bank |
| BNZ | ~8.60% | Subject to change; confirm with bank |
| Westpac | ~8.65% | Subject to change; confirm with bank |
| Kiwibank | ~8.60% | Subject to change; confirm with bank |
These rates are indicative only and change frequently. Always confirm the current servicing rate with each bank or via a registered mortgage adviser.
RBNZ DTI Caps: What They Mean for You
In addition to the servicing test, RBNZ implemented Debt-to-Income (DTI) ratio speed limits in 2024. These do not directly prevent individual borrowers from exceeding the caps, but restrict how much of each bank's total new lending can be above the cap.
RBNZ DTI limits as of mid-2024
| Borrower Type | DTI Cap | Speed Limit | Max Loan at $120K Income |
|---|---|---|---|
| Owner-occupier | 6x gross income | 20% of new lending | $720,000 |
| Property investor | 7x gross income | 20% of new lending | $840,000 |
Note: Speed limits mean banks can still lend above the cap for up to 20% of new loans. If you exceed the DTI cap, your application is not automatically declined, but requires additional justification.