Fixed vs Floating Mortgage NZ — How to Choose

Fixed or floating is the first real decision a New Zealand home borrower makes after picking a lender. The choice affects monthly payment certainty, the flexibility to repay early, what happens if you sell or refinance, and how exposed your household budget is to a future move in interest rates.

This guide explains how each option works in the NZ market, how rates are set, what break fees are and when they apply, the splitting strategies most experienced borrowers use, and how to decide which mix is right for your situation. It does not quote specific rates — those move week to week and any specific number ages out of date fast.

Around 170%

household debt as a share of disposable income

NZ households carry debt at around 170% of disposable income

The Reserve Bank publishes the household debt-to-disposable-income ratio in its statistics releases. The level matters because most NZ household debt is mortgage debt — making the fixed-vs-floating decision one of the most consequential financial choices a Kiwi household makes.

Source:  Reserve Bank of New Zealand (RBNZ)  · RBNZ key statistics — household debt · verified 2026-06-09

The core difference

A fixed-rate mortgage locks in an interest rate for a set period — six months to five years in NZ. During that period, your repayments do not change regardless of what happens to wholesale rates, the OCR, or the lender's floating rate. At the end of the fixed term, the loan rolls onto either a new fixed term (at whatever rate is available then) or onto the floating rate, depending on what you choose.

A floating-rate mortgage (variable in some markets) carries a rate that the lender can change at any time, usually following moves in the Reserve Bank's Official Cash Rate. You give up payment certainty but gain the ability to repay any amount at any time without break-fee exposure.

How NZ mortgage rates are set

Understanding the source of each rate clarifies which lever you are exposed to.

Floating rates

A bank's published floating rate reflects three things: the cost of short-term wholesale funding (which tracks the OCR), the bank's margin, and competitive positioning. When the Reserve Bank moves the OCR, banks typically pass most of the move into their floating rates within a few weeks. The margin component can drift independently — for example, when funding markets tighten, banks may widen their margin even if the OCR is unchanged.

Fixed rates

Fixed rates are priced off the wholesale interest-rate curve — the market's expectation of where the OCR will sit over the term being fixed. A 1-year fixed rate reflects the average expected OCR over the next year plus a margin; a 5-year fixed rate reflects the average expected OCR over five years plus a margin and a term premium.

A counter-intuitive consequence: fixed rates can fall in anticipation of an OCR cut, before the cut actually happens. They can also rise in anticipation of an increase. By the time the Reserve Bank announces a decision, much of the move is often already priced in.

Break fees — what they are and when they apply

If you exit a fixed-rate loan before the end of the fixed term, the lender may charge a break fee. The fee compensates the bank for the cost of unwinding the position they took to fund your loan at the agreed rate. Three triggers typically apply:

• Selling the property and discharging the loan.
• Refinancing to a different lender before the fixed term ends.
• Making lump-sum repayments beyond the contractual allowance (most lenders allow some annual lump-sum without penalty — read the loan contract for the limit).

The Credit Contracts and Consumer Finance Act 2003 requires the lender to disclose how the break fee is calculated, and to provide a written estimate on request. The fee is the present value of the lender's loss — if wholesale rates have risen since you fixed, the break fee can be small or zero; if rates have fallen, it can be substantial. Always ask for a written break-fee estimate before triggering an exit.

Choosing a fixed term

The five common fixed terms (1, 2, 3, 4 and 5 years) trade off certainty against flexibility:

• Short terms (6 months, 1 year, 2 years) — you re-price often, which exposes you to upward moves but lets you capture downward moves quickly. Break fees on shorter terms are typically smaller because there is less time left to unwind.
• Medium terms (2-3 years) — the most commonly used in NZ. Balance of certainty and re-pricing optionality.
• Long terms (4-5 years) — maximum certainty, but you give up the chance to re-price into a lower rate if the market moves. Break fees can be material if you exit early.

What term is "right" depends on three things: how confident you are in your view of where rates are heading, how stable your income and household plans are over the term, and whether you might want to sell or refinance during the term. A common pattern is to take a slightly shorter term when you suspect rates may fall, and a longer term when you suspect they may rise — but acting on a confident view of future rates is essentially betting against the market, which has already priced its consensus view into the rate you are being offered. Most experienced borrowers pick a term that fits their household planning horizon rather than their rate forecast.

Splitting the loan

NZ banks allow you to divide a single mortgage across multiple terms and rate types — for example:

• Three roughly equal portions fixed for 1, 2 and 3 years respectively
• A smaller slice on the floating rate for lump-sum repayments

Splitting achieves three things at once:

1. Staggered re-pricing. No single date exposes the whole loan to a re-price. If rates have moved sharply on one re-price date, you only re-price one portion at that rate.
2. Floating flexibility. The floating portion can be repaid in lumps without break fees. If you receive bonuses, tax refunds, or sell another asset, you can pay the floating slice down.
3. Diversified rate view. You are not making a single high-conviction call on where rates are heading.

The cost of splitting is mild — some lenders charge a small administration fee per split, and managing multiple terms requires keeping track of multiple re-price dates. Most lenders' online banking now shows all splits in one view.

Refinancing

Refinancing means moving your loan from one lender to another. The reasons are usually a better rate, a different product structure (e.g. an offset facility), or a cash-contribution incentive from the new lender.

A clean refinance comparison requires netting four numbers:

1. Break fees on existing fixed terms with your current lender.
2. Lawyer fees and registration costs for the new loan.
3. Cash contribution incentive from the new lender (usually a four-figure sum for refinancing).
4. Interest savings from the new rate, calculated over the period you expect to hold the loan.

Item 4 is the one most borrowers eyeball wrong — it is easy to be drawn in by a small rate difference that, when modelled over the actual holding period, does not cover items 1-3. A broker or licensed adviser can model the net effect before you commit.

When each makes sense

Lean fixed if you...

• Need payment certainty to keep the household budget predictable.
• Do not expect to make lump-sum repayments during the term.
• Are not planning to sell or refinance during the term.
• Want to lock in a known rate while you are uncertain about your household income changing.

Lean floating if you...

• Expect to repay or refinance the loan soon.
• Want to make irregular lump-sum repayments.
• Are bridging between two properties (a planned short hold).
• Are managing a smaller residual loan that you intend to repay aggressively.

Split if you...

• Want a balance of certainty and flexibility.
• Have a meaningful loan size where the small splitting overhead is justified relative to the rate-risk diversification you get.
• Want to smooth re-pricing risk across multiple maturities.

Next steps

For current NZ mortgage rates across the bank panel, see Home-Loans.co.nz. For an editorial overview of the NZ mortgage market — fixed-rate trends, lender notes and refinance walk-throughs — visit our mortgages hub. When you are ready to model the actual numbers for your loan, you can request a mortgage consultation — your enquiry is referred to Evolve Group Limited (FSP711891), a licensed Financial Advice Provider.

Frequently asked questions

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This article is general information about NZ mortgages, not regulated personal financial advice. Interest rates and lender policies change continuously — confirm current rates with the lender and a licensed adviser before relying on a specific structure. Read our methodology and sources.