Mortgage payment calculator
See what your home loan will actually cost per week, fortnight or month — and how much of that is interest.
Where your payments go
Cumulative principal vs interest paid over the loan term — notice how much goes to interest early on.
What this means for you
Enter a household income above to see how this repayment compares to your income, and how a bigger deposit would change it.
Compare scenarios
See how a bigger deposit or a shorter term would change your repayment and total interest.
| Scenario | Repayment | Year 1 vs current | Total interest | Full term vs current |
|---|---|---|---|---|
| Current | $0 | — | $0 | — |
| Bigger deposit (+$30k) | $0 | $0 | $0 | $0 |
| Shorter term (−5yr) | $0 | $0 | $0 | $0 |
"Full term vs current" compares total interest paid, since the shorter-term scenario pays the loan off in fewer years — a fair like-for-like isn't possible on total repaid alone.
Assumptions & sources
Major-bank carded fixed rates; Stats NZ Household Income and Living Survey (HILS) for the income benchmark.
1 July 2026
17 July 2026
Standard reducing-balance (table) loan amortisation, compounding at your chosen repayment frequency.
Loan principal and interest only.
Rates, insurance, body corporate fees, low-equity margins, break/refix fees. The income comparison deducts PAYE income tax only — not ACC levies or KiwiSaver contributions.
$115,000 is an approximate NZ median gross household income, informed by Stats NZ income trends. An exact, single published HILS 2025 median household figure wasn't available at time of writing — enter your own household income above for a figure specific to you.
Related reading
What does the OCR rate hike mean for you?
The Reserve Bank just lifted the OCR to 3.50% — what it means for your mortgage, savings and everyday costs.
Read article →
Fixed vs floating: how to choose your mortgage rate
Locking in feels safer, but floating has real advantages too. Here's how to decide which fits you.
Read article →How mortgage repayments are calculated
This tool uses the standard reducing-balance formula that New Zealand banks use for table (principal & interest) mortgages — the same repayment amount every period, with the mix of interest and principal shifting over time. Here's what each part of the calculation means:
- Principal — The loan amount — what's left after your deposit is subtracted from the purchase price. This is the balance interest is charged on.
- Interest rate — The annual rate your bank charges on the outstanding balance, applied proportionally to however often you repay (weekly, fortnightly or monthly).
- Loan term — How many years you have to repay the loan in full. A longer term lowers each repayment but increases the total interest you pay over the life of the loan.
- Repayment frequency — Weekly, fortnightly or monthly. Paying more often shaves a small amount off total interest, since the balance reduces slightly sooner each time.
- Amortisation — Why early repayments are mostly interest: the balance is largest at the start, so interest makes up a bigger share of each repayment. As the balance shrinks, more of each repayment goes toward principal instead.
- The formula, in plain English — Each repayment first covers that period's interest charge, and whatever's left over goes toward reducing the loan balance. Repeat that every period for the full term, and the balance reaches exactly zero on the final repayment.
The interest rate defaults to a representative rate based on major-bank carded rates as advertised in July 2026. Fixed-rate NZ mortgages currently range from around 4.5% for a 6-month term up to around 5.5% for a 5-year term, though special rates for borrowers with 20%+ equity are often a little lower, and rates move regularly — always check the current rate with your bank or a mortgage adviser before making decisions.
Example: $700,000 Auckland mortgage
Sarah and James are buying an $875,000 home in Auckland with a 20% deposit, leaving them with a $700,000 mortgage over 30 years.
At 6% interest, their estimated repayment would be approximately $4,197 per month.
If their rate increased to 7% at their next refix, repayments would rise to approximately $4,657 per month — roughly $460 more each month, or about $5,520 more a year.
That's the kind of shift a single percentage point can make on an Auckland-sized mortgage — which is why comparing fixed-term options before you refix is worth the ten minutes it takes.
What this doesn't include
- Council rates, water rates, and home & contents insurance
- Body corporate fees or ground rent for units, apartments and cross-lease sections
- Low-equity margins some banks add when your deposit is under 20%
- One-off costs like legal fees, LIM reports and building inspections
For a full picture of what you could afford, try the borrowing power calculator and the monthly budget calculator next.
Frequently asked questions
Use the rate you've been quoted, or the current advertised rate for the fixed term you're considering. As of July 2026, advertised rates from the major banks run roughly from 4.5% (6-month fixed) to 5.5% (5-year fixed), with lower special rates sometimes available for borrowers with 20%+ equity.
No — this is the loan principal and interest only. Rates, insurance, and body corporate or ground rent are separate ongoing costs to budget for on top of this figure.
Banks use your exact settlement date and compounding method, and account for any offset or revolving credit structure, which can shift the number slightly. Use this calculator to compare scenarios, then confirm the exact figure with your lender.
