FREE MORTGAGE TOOL
Mortgage Repayment Calculator
Work out what your mortgage repayments would be, and how much interest you would pay over the life of the loan. This mortgage repayment calculator uses the standard amortisation formula New Zealand banks apply, with live rates.
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COMMON QUESTIONS
Mortgage repayments are worked out using the standard loan amortisation formula, the same method every New Zealand bank uses. It takes three inputs: the loan amount, the interest rate, and the loan term. From those it calculates a fixed regular repayment that covers both the interest charged and enough principal to clear the loan by the end of the term.
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Each repayment is split between interest and principal, but the split shifts over time. Early on, most of your payment goes to interest because the balance is high. As the balance falls, more of each payment goes toward the principal. This is why the first few years of a mortgage feel like slow progress on the loan itself.
The rates shown in the calculator are pulled from ratesapi.nz, an independent service that collects published mortgage rates directly from New Zealand lenders' websites. What you see reflects each bank's current advertised rate rather than a figure entered manually.
The calculator shows eight New Zealand lenders: ANZ, ASB, BNZ, Kiwibank, Westpac, TSB, Co-operative Bank and SBS. For each bank it shows the lowest advertised rate for the fixed period you have selected, labelled either Standard or Special.
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Standard rates are a bank's general carded rate. Special rates are lower but come with lender conditions, commonly a minimum deposit or equity level, and sometimes other requirements. Your bank can confirm what you would qualify for.
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You can choose a fixed period from floating through to five years, and the list reorders to show the lowest rate first. If you already know your rate, you can enter it manually instead.
Not necessarily. Advertised rates are a starting point. The rate you are offered depends on your deposit or equity, your income, the type of property, and whether you negotiate. Rates on investment lending can differ from owner-occupied lending. Rates also change frequently, so the rate shown may differ from the rate available when you apply. The figures are indicative only and do not take your circumstances into account.
Principal and interest repayments cover both the interest charged and a portion of the amount borrowed, so the loan balance reduces over time and is fully repaid by the end of the term. This is the standard structure for owner-occupied home loans in New Zealand.
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Interest-only repayments cover just the interest charged. The loan balance does not reduce, so at the end of the interest-only period you still owe the full amount borrowed. Repayments are lower during that period, but you pay more interest overall because the balance never falls. Interest-only is more commonly used on investment lending and is usually approved for a limited period rather than the full term.
Total interest depends on the loan amount, the interest rate, and the term. Because interest is charged on the outstanding balance, a longer term means more interest overall even though each repayment is smaller. On a 30-year mortgage, total interest paid can approach or exceed the amount originally borrowed, depending on the rate.
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The calculator shows total interest alongside total repaid, so you can see the full cost of borrowing rather than just the regular repayment amount. Shortening the term or making extra repayments both reduce total interest, because they reduce the balance the interest is charged on.
It can, depending on how the repayments are structured. If your weekly or fortnightly repayment is simply the monthly amount divided proportionally, the difference is small. But many people making fortnightly repayments end up paying the equivalent of thirteen months a year rather than twelve, because there are 26 fortnights in a year rather than 24. That extra amount goes directly to the principal.
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Whether this applies depends on how your lender calculates the repayment. It is worth checking with your bank rather than assuming.
The calculator defaults to a current advertised rate, and you can enter a custom rate to model a different scenario. Fixed rates in New Zealand are typically set for a term of six months to five years, after which the loan is refixed at whatever rates apply then.
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The calculator assumes a single fixed rate for the full term, which is a simplification. In practice most New Zealand borrowers refix several times over the life of a mortgage, and the rate will change each time. Modelling a higher rate than the current one is a useful way to see how repayments would change if rates rose at your next refix.
This mortgage repayment calculator shows principal and interest on the loan itself. It does not include rates, insurance, body corporate levies, maintenance, or bank fees, all of which add to the true cost of owning a property. It assumes a single fixed rate for the full term and standard amortisation, rather than the refixing most borrowers go through. And it does not assess serviceability, whether a lender would approve the loan based on your income and expenses, which is a separate test. Treat the result as an indication of the repayment, not a lending offer.
Figures are indicative only and general in nature. They do not take your personal circumstances into account and do not constitute lending or financial advice. Interest rates, lender criteria, and serviceability requirements change over time and vary by lender. Rate data is sourced from ratesapi.nz and may not reflect the rate available to you.