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Mortgage Repayment Calculator

Calculate NZ home loan repayments with current mortgage rates. Compare floating vs fixed, monthly vs fortnightly, and see total interest cost.

By Konstantin IakovlevPublished 28 March 2026Last reviewed
Data stays on your deviceRBNZ market data

About this calculator

This calculator uses RBNZ interest rate data + standard PMT formula. Reference: Standard amortisation formula. Last consulted 15 March 2026.

Current NZ mortgage benchmarks

Indicative average rates as of Q2 2026 (varies by bank)
  • •Typical 1-yr fixed rate: ~6.2–6.6%
  • •Typical 2-yr fixed rate: ~6.0–6.4%
  • •Typical floating rate: ~7.5–8.0%
  • •Most common term: 30 years
  • •RBNZ OCR (sets bank rates): Currently 3.50% (reviewed 8 weekly)
  • •LVR cap (owner-occupier): ≤80%

Source: RBNZ — Interest rates

Disclaimer

This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available IRD data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.

How mortgage repayments are calculated

Repayments use the standard amortisation formula. Each payment covers interest on the remaining balance plus a small principal reduction — the principal share grows over time.

  1. 1

    Convert annual rate to periodic rate

    i = annual_rate ÷ 12  (monthly)  |  ÷ 26 (fortnightly)  |  ÷ 52 (weekly)

    Banks typically compound at the payment frequency, so the divisor matches.

  2. 2

    Calculate total number of payments

    n = term_years × 12 (or 26, or 52)

    30-year monthly = 360 payments. 30-year fortnightly = 780.

  3. 3

    Apply the PMT (annuity) formula

    Payment = P × i × (1+i)ⁿ ÷ ((1+i)ⁿ − 1)

    P = loan principal. This gives a constant repayment that fully retires the loan over n periods.

  4. 4

    Calculate total interest paid

    Total Interest = (Payment × n) − P

    On a $600k loan at 6.5% over 30 years, interest alone tops $750k.

  5. 5

    Compare payment frequencies

    Weekly_total ≈ Monthly_total × 12 ÷ 52 (with slight difference due to compounding)

    Fortnightly pays off ~3-5 years earlier than monthly because 26 fortnights = 13 'monthly equivalents'.

Worked example

Inputs: $600,000 loan, 6.5% rate, 30-year term, monthly

Result: Monthly: $3,792 · Total interest: $765,257 · Total cost: $1,365,257

Frequently Asked Questions

What are typical mortgage rates in NZ?
NZ mortgage interest rates vary by lender, loan type, and fixed term. As of 2026-27, typical one-year fixed rates are around 5.5% to 6.5%, two-year fixed rates around 5.5% to 6.5%, and five-year fixed rates around 5.8% to 6.8%, depending on the lender. Floating (variable) rates generally sit 1–2 percentage points higher than the best fixed rates. The Reserve Bank of New Zealand (RBNZ) sets the Official Cash Rate (OCR), which influences mortgage rates — as the OCR rises, mortgage rates tend to follow. For comparison, on a $500,000 mortgage over 30 years, a 1% difference in interest rate changes the monthly repayment by approximately $280 and total interest paid by around $100,000. Always compare rates across multiple lenders and consider break fees if switching from a fixed term. Source: Reserve Bank of NZ (rbnz.govt.nz).
What deposit do I need for a house in NZ?
Most banks in New Zealand require a minimum 20% deposit for owner-occupied properties, in line with the Reserve Bank of New Zealand's (RBNZ) loan-to-value ratio (LVR) restrictions. For example, on a $700,000 home, that means a $140,000 deposit. First home buyers may qualify for a 10% deposit through some bank policies or the Kāinga Ora First Home Loan scheme (available to applicants meeting income and house price caps). Investment properties typically require a 35% deposit under RBNZ LVR rules. A smaller deposit generally means a higher interest rate through a low-equity premium. KiwiSaver funds can be withdrawn (after three years of membership) to boost your deposit for a first home purchase, which can significantly reduce the savings time required. Source: RBNZ LVR Policy (rbnz.govt.nz) and Kāinga Ora (kaingaora.govt.nz).
How is mortgage interest calculated in NZ?
Mortgage interest in New Zealand is calculated daily on the loan balance and charged in arrears. Most NZ banks use a 365-day year. The annual rate is divided by 365 to get the daily rate, which is multiplied by your outstanding balance and accumulated through the period. For a $500,000 mortgage at 6.5%, daily interest is about $89 — over a 30-year term, you pay around $637,000 in total interest. Floating rates change with the OCR (Official Cash Rate). Fixed rates lock the rate for 6 months to 5 years. Source: RBNZ, NZ banks.

The NZ mortgage repayment calculator estimates your regular home loan repayments based on the loan amount, interest rate, and loan term. It covers both principal-and-interest and interest-only repayment structures.

How this calculator works

For principal-and-interest loans, the calculator uses the standard annuity formula: M = P[r(1+r)^n] / [(1+r)^n - 1], where P is the principal, r is the periodic interest rate, and n is the total number of payments. For interest-only loans, the repayment is simply the principal multiplied by the periodic interest rate. Results are shown weekly, fortnightly, or monthly.

Typical NZ Mortgage Interest Rates (indicative, mid-2025)

1-year fixed5.59% - 6.29%
2-year fixed5.29% - 5.99%
3-year fixed5.39% - 5.89%
5-year fixed5.59% - 5.99%
Floating6.74% - 7.49%

Rates vary by lender and are subject to change. Check your bank for current rates.

Loan-to-Value Ratio (LVR) Restrictions

Owner-occupierMax 80% LVR (20% deposit required)
InvestorMax 65% LVR (35% deposit required)
First home buyer exemptionsMay qualify for higher LVR with conditions

Reserve Bank of NZ LVR restrictions as of 2025.

Worked Examples

$600,000 loan, 5.79% interest, 30-year term, principal and interest

Monthly repayment: $3,518. Total interest over the loan: $666,480.

  1. Monthly interest rate: 5.79% / 12 = 0.4825%
  2. Number of payments: 30 x 12 = 360
  3. Monthly payment using annuity formula: $3,518
  4. Total repaid: $3,518 x 360 = $1,266,480
  5. Total interest: $1,266,480 - $600,000 = $666,480

$450,000 loan, 5.49% interest, 25-year term, principal and interest

Fortnightly repayment: $1,343. Total interest over the loan: $422,700.

  1. Fortnightly interest rate: 5.49% / 26 = 0.2112%
  2. Number of fortnightly payments: 25 x 26 = 650
  3. Fortnightly payment: $1,343
  4. Total repaid: $1,343 x 650 = $872,950
  5. Total interest: $872,950 - $450,000 = $422,950

$800,000 loan, 6.50% interest, interest-only for 2 years

Monthly interest-only repayment: $4,333.

  1. Monthly interest: $800,000 x 6.50% / 12 = $4,333.33
  2. No principal is repaid during the interest-only period
  3. After 2 years, the full $800,000 must be repaid or switched to P&I

Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.

Last reviewed:

Official Sources

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