Example result based on the prefilled values.
Repayment per Period
NZ$1,534.61
Monthly Equivalent
NZ$3,324.99
Total Repayment
NZ$1,196,995.80
Total Interest
NZ$696,995.80
LVR
0.00%
Continue your plan
Useful next calculations
When to use this calculator
- Before comparing lenders, brokers, or repayment options.
- When you want to test how a different deposit, rate, or term changes affordability.
- When you need a quick estimate before using a formal quote or agreement in principle.
- When you are stress-testing your budget against a potential rate rise to see the impact on monthly payments.
- When you want to understand the full cost of borrowing — not just the monthly figure — before you commit.
A realistic New Zealand planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Loan Amount (NZ$)
NZ$600,000
Interest Rate (%)
5%
Loan Term (years)
NZ$600,000
Repayment Frequency
Fortnightly
After entering these figures, review repayment per period, monthly equivalent and total repayment together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Repayment per Period
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Monthly Equivalent
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Total Repayment
This is the headline outcome of the calculation, but it is most useful when read alongside the supporting metrics below it rather than in isolation. Try changing one input at a time and watching how this total moves to understand which driver has the biggest impact.
Total Interest
This shows the long-run cost of borrowing beyond the original principal, which is especially useful when comparing terms or weighing up overpayment options. A shorter term usually cuts this figure significantly even if the monthly payment rises.
LVR
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator uses the standard mortgage amortisation formula applied at your chosen repayment frequency — weekly (52 payments per year), fortnightly (26), or monthly (12). New Zealand borrowers commonly choose fortnightly repayments because the extra payments each year reduce the principal faster and cut total interest considerably over a 25–30-year term. The periodic interest rate is derived by dividing your annual rate by the number of payment periods, then applying the compound interest formula. The LVR figure is relevant to RBNZ lending restrictions: owner-occupiers generally need at least a 20% deposit, meaning an LVR at or below 80%, to access mainstream lending without additional conditions.
Note that this calculator assumes a constant interest rate for the full loan term and does not model refix decisions, rate changes, or lump-sum repayments. In practice, most New Zealand mortgages are fixed for one to five years at a time, after which you renegotiate with your bank. If you are comparing lenders or rate types, model each scenario separately using the interest rate for that product. The results here are indicative — your bank is required to provide a full disclosure statement and credit contract before any mortgage offer becomes binding under the Credit Contracts and Consumer Finance Act (CCCFA).
Common mistakes
- !Using an assumption that is not supported by a current local quote, bill, statement or official source.
- !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
- !Mixing monthly and annual inputs without converting them consistently.
- !Forgetting location-specific taxes, fees, eligibility rules or payroll deductions where they apply.
- !Testing only one scenario instead of checking how a cautious assumption changes the result.
What to do next
- Run a second scenario with a cautious assumption so you can see the downside clearly.
- Compare the result with the related calculators below before making a decision.
- Check current local rules, eligibility and provider terms before applying or committing money.
- Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.
- Use the result to prepare better questions for a lender, provider, adviser or employer rather than treating it as a final answer.
Frequently asked
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