New Zealand Mortgage Calculator

Calculate your NZ home loan repayments in weekly, fortnightly or monthly payments. Includes RBNZ LVR checker, fixed vs floating rate comparison, and OCR sensitivity analysis. All figures in NZD.

$
$
%
Monthly Payment
NZ$3,988
Principal and interest
Loan Amount
NZ$600,000
Deposit: 20.0%
LVR
80.0%
Standard — no RBNZ restriction
Total Interest
NZ$835,603
Over 30 years
LVR 80.0%: Standard — no RBNZ restriction. RBNZ rules: below 80% is standard lending; 80-90% is restricted (limited bank appetite); above 90% is very rare unless new build.

Weekly and fortnightly payments are equivalent to making 13 monthly payments per year instead of 12 — saving significant interest over the life of the loan.

FrequencyPaymentAnnual CostTotal InterestInterest Saved
WeeklyNZ$920NZ$47,853NZ$835,603—
FortnightlyNZ$1,841NZ$47,853NZ$835,603—
MonthlyNZ$3,988NZ$47,853NZ$835,603—

Weekly payments reduce interest because you pay down principal faster. The saving is the extra payment effect, not a rate reduction.

The RBNZ Official Cash Rate (OCR) directly drives floating and fixed rates. Each 0.25% OCR change typically moves mortgage rates by a similar amount.

OCR ChangeNew RateMonthly PaymentChange vs Current
-0.50% (OCR cut)6.49%NZ$3,788-NZ$199
-0.25% (OCR cut)6.74%NZ$3,888-NZ$100
Current6.99%NZ$3,988—
+0.25% (OCR rise)7.24%NZ$4,089+NZ$101
+0.50% (OCR rise)7.49%NZ$4,191+NZ$203

How to Use This NZ Mortgage Calculator

Enter your loan amount, interest rate, loan term, and preferred payment frequency (weekly, fortnightly, or monthly). The calculator shows your repayment amount, total interest paid, and compares how much you save by choosing weekly or fortnightly payments over monthly.

Fixed vs Floating Rate in New Zealand

Most NZ banks support weekly and fortnightly repayments without extra cost. Paying weekly instead of monthly can save tens of thousands of dollars over the life of the loan.

The Formula

Monthly Payment = P × [r(1+r)^n] ÷ [(1+r)^n − 1]

Where:
P = Principal loan amount
r = Monthly interest rate (annual rate ÷ 12)
n = Total number of monthly payments

Weekly Payment ≈ Monthly Payment × 12 ÷ 52
Fortnightly Payment ≈ Monthly Payment × 12 ÷ 26

NZ banks calculate interest daily on the outstanding balance.

Because weekly and fortnightly payments result in 13 or 26 equivalent payments per year rather than 12, you repay the principal faster and pay significantly less total interest. On a $600,000 mortgage at 6.5%, switching from monthly to weekly payments saves approximately $35,000 in interest and cuts about 2 years off a 30-year term.

Example

Ben and Aroha Buying in Auckland

Ben and Aroha have a $680,000 mortgage at 6.50% over 30 years. They are comparing payment frequency options.

Loan Amount$680,000
Interest Rate6.50%
Loan Term30 years
Monthly Payment$4,298
Fortnightly Payment$2,149
Weekly Payment$1,075
Total Interest (monthly)$867,200
Total Interest (fortnightly)~$820,000
Interest Saving (fortnightly)~$47,200
Time Saved (fortnightly)~2.5 years

Frequently Asked Questions

LVR stands for Loan-to-Value Ratio — your loan as a percentage of the property value. The RBNZ restricts high-LVR lending to control housing market risk. For owner-occupiers, lending above 80% LVR is restricted — only a small portion of bank lending can go into this category. Above 90% LVR is almost impossible for existing homes unless you qualify for a Kainga Ora First Home Loan, which allows a 5% deposit for eligible buyers.
Weekly and fortnightly payments save significant interest because you effectively make the equivalent of 13 monthly payments per year instead of 12. On a $600,000 mortgage at 6.5%, switching from monthly to fortnightly can save over $40,000 in interest and cut approximately 2 to 3 years off your loan term. Most NZ banks support all three frequencies at no extra cost — weekly is the most powerful option if it aligns with your pay cycle.
Fixed rates provide certainty for 6 months to 5 years but restrict extra repayments and incur break fees if you need to exit or restructure early. Floating rates move with the RBNZ OCR and allow unlimited extra repayments without fees. A popular NZ strategy is a split loan — fix 50 to 70% for budget certainty while leaving the rest floating to accommodate lump sum payments from bonuses or windfalls. You refix when each tranche expires at the prevailing rate.
The RBNZ OCR directly influences all NZ mortgage rates. When the OCR rises, banks raise both floating and fixed rates within days to weeks. A 0.25% OCR increase typically adds $30 to $50 per month on a $500,000 floating mortgage. Fixed rate mortgages are protected from OCR changes until your fixed term expires. This is why many Kiwis fix their rate when the OCR is uncertain — to gain payment certainty for the fixed period.
A revolving credit facility is a home loan that works like an overdraft with a limit set at your mortgage balance. Your salary is deposited directly into the account, immediately reducing your balance and the daily interest calculated. Bills are paid from the account as they fall due. Having your salary sit in the account for even 2 to 3 weeks before bills are paid can save the equivalent of 0.5 to 1.0% in effective interest. It requires financial discipline to work effectively — undisciplined spending can cost more than it saves.

Related New Zealand Calculators

$First Home Calculator $Bright-Line Calculator $Council Rates Calculator $Stamp Duty Calculator $Affordability Calculator $LMI Calculator

Sources & References