Property Deal Analyser NZ 2026/27
This page replaces the four or five separate calculations investors normally chain together when sizing up a rental. It takes the purchase price, the deposit, the lending terms, the rent and every operating cost, and returns the numbers that actually decide whether a deal works: the weekly cash position, the gross and net yield, the cash-on-cash return on the money you put in, the rent the property would need to break even, and the interest rate at which it would. It applies New Zealand's residential rental loss ring-fencing rules properly, which matters more than most calculators admit, because a rental loss does not generate a tax refund against your salary and has not since the 2019-20 income year. It carries forward instead, so the after-tax weekly cost of a loss-making rental is usually identical to the before-tax cost. The page also includes a stress row two percent above your chosen rate, on the basis that a deal which only survives at today's rate is a bet on the rate rather than an investment. The output is deliberately one scannable card followed by the workings, so you can compare properties quickly without losing the detail that explains the answer.
Net operating income (NOI) = rent collected less rates, insurance, body corporate, maintenance and management. It deliberately excludes the mortgage, so it measures the property rather than your financing.
Weekly cash position = (NOI less the annual table mortgage repayment) divided by 52. The repayment uses the standard table formula, principal and interest.
Gross yield = annual rent at full occupancy / purchase price. Net yield = NOI / purchase price. Cash-on-cash = annual cash flow / deposit.
Tax = (NOI less year-one mortgage interest) taxed at your marginal rate, but only where that figure is positive. A loss is ring-fenced and carried forward under subpart EL of the Income Tax Act 2007, so it produces no refund.
Break-even rent solves for the weekly rent at which NOI equals the annual repayment. Break-even rate solves for the interest rate at which the annual repayment equals NOI, by bisection to 12 decimal places.
Hold period grows the property at your chosen rate, amortises the loan on its original schedule, and adds accumulated cash flow. Rent and costs are held flat in nominal terms, which is conservative on rent and optimistic on costs.
Not financial advice. Last verified: .
What the property earns and spends
| Rent collected (50 of 52 weeks) | $32,500.00 |
| Less council rates | $3,200.00 |
| Less insurance | $1,800.00 |
| Less body corporate | $0.00 |
| Less maintenance (1% of value) | $5,800.00 |
| Less management (8% of rent) | $2,600.00 |
| Net operating income | $19,100.00 |
| Less mortgage on $377,000.00 | $27,855.05 |
| Annual cash position | -$8,755.05 |
| Weekly cash position | -$168.37 |
Tax, and why the loss does not help you
| Net operating income | $19,100.00 |
| Less year-one mortgage interest | $23,437.38 |
| Taxable rental result | -$4,337.38 |
| Tax payable at 33% | $0.00 |
| Loss ring-fenced and carried forward | $4,337.38 |
| Weekly cash position after tax | -$168.37 |
A ring-fenced loss produces no refund in the year it arises. It waits until the property makes a profit, which on a negatively geared purchase can be many years away.
Break-even, and what happens if rates rise
| Rent needed to break even | $840.33 |
| Actual rent | $650.00 |
| Shortfall against break-even | $190.33 |
| Interest rate that breaks even | 3.01% |
| Stress test at 8.25%: annual repayment | $33,987.30 |
| Weekly cash position under stress | -$286.29 |
| Extra weekly cost if rates rise 2% | $117.93 |
Total return over 10 years
| Value after 10 years at 3% growth | $779,471.50 |
| Loan balance remaining | $317,576.18 |
| Equity at the end | $461,895.32 |
| Less deposit originally invested | $203,000.00 |
| Plus accumulated cash flow | -$87,550.46 |
| Total gain | $171,344.86 |
Rent and costs are held flat in nominal terms over the hold period. In practice both rise, which helps the cash position and hurts the running costs, roughly offsetting on a well-managed property.
The Weekly Number Is The One That Decides
Investors tend to lead with yield because it is the figure in the advertisement. Yield does not tell you whether you can hold the property. The weekly cash position does, because it is the amount that leaves your account whether or not the market cooperates.
On the worked example that number is -$168.37 a week. Over a year that is $8,755.05 of your own income going into an asset that is, on paper, performing exactly as expected. That is not a failure of the deal. It is what a 5.83% gross yield looks like when money costs 6.25%, and it is the normal condition of residential property in New Zealand at present. The question is not whether the number is negative but whether you can comfortably fund it for as long as you intend to hold, including in a year when you also lose a tenant, replace a roof or change jobs.
Worked Example: $580,000 At 35% Deposit
Take the defaults. A $580,000.00 purchase with a 35% deposit means $203,000.00 of your own money and a $377,000.00 loan. At 6.25% over 30 years the repayment is $2,321.25 a month, or $27,855.05 a year.
The property rents for $650.00 a week. Allowing two weeks of vacancy, you collect 50 weeks, which is $32,500.00. Against that, rates are $3,200.00, insurance $1,800.00, maintenance at 1% of value is $5,800.00, and management at 8% of rent collected is $2,600.00. Total operating costs are $13,400.00, leaving net operating income of $19,100.00.
NOI of $19,100.00 against a mortgage of $27,855.05 leaves a shortfall of $8,755.05, which is the $168.37 a week. Gross yield is 5.83%, net yield is 3.29%, and cash-on-cash return on the $203,000.00 deposit is -4.31%.
The Ring-Fencing Rule Removes The Tax Cushion
A common mental model is that a negatively geared rental is partly funded by a tax refund. In New Zealand that has not been true since the 2019-20 income year.
Under subpart EL of the Income Tax Act 2007, residential rental losses are ring-fenced. They cannot be offset against salary, wages, business income or anything else. They are carried forward and deducted only when the residential property produces income in a later year.
On the worked example, net operating income of $19,100.00 less year-one interest of $23,437.38 gives a taxable result of -$4,337.38. At a 33% marginal rate an offsettable loss would have been worth $1,431.34. Instead it is worth nothing this year. It joins a carried-forward balance and waits, potentially for a decade, until the property turns a taxable profit.
This is why the after-tax weekly cost on this page is identical to the before-tax cost. Any calculator showing a rental loss generating a refund against your salary is applying rules that were repealed years ago.
Break-Even Rent States The Problem Plainly
The break-even rent is the weekly figure at which the property covers its own costs including the mortgage. Here it is $840.33, against a market rent of $650.00.
The gap of $190.33 a week is not a rounding issue. It says the property would need to charge 29% more than the market is currently paying before it stopped consuming cash. No amount of careful management closes a gap that size. It can only be closed by rents rising substantially, by interest rates falling substantially, or by paying down principal.
The break-even interest rate makes the same point from the other direction: at 3.01% this property funds itself. Rates would need to roughly halve. Both figures are worth writing down before you buy, because they define what you are actually relying on.
Stress The Rate, Not The Rent
Most investors stress test by imagining a vacancy. That is the wrong risk to worry about most. A vacancy is a few weeks of lost rent; a rate rise is permanent until it is not.
Two percent on this loan takes the annual repayment from $27,855.05 to $33,987.30 and widens the weekly shortfall from $168.37 to $286.29. That is an extra $117.93 every week, $6,132.25 a year, for as long as the higher rate persists. If that figure would force you to sell, the deal is too tight regardless of what the yield says. Our Mortgage Stress Test Calculator runs the same logic across a wider range of rates.
Where The Return Actually Comes From
Over ten years at 3% growth the property rises from $580,000.00 to $779,471.50 while the loan amortises down to $317,576.18. Equity ends at $461,895.32. Subtract the $203,000.00 deposit and the $87,550.46 of cash you contributed along the way, and the total gain is $171,344.86.
Every dollar of that came from capital growth and principal repayment. None of it came from rent. That is a legitimate way to invest, and it has worked well in New Zealand for a long time, but it should be a decision rather than an accident. If growth comes in at 1% instead of 3%, the arithmetic changes completely, and the ten years of weekly contributions do not come back.
Check The Lending Before You Fall In Love
Two constraints sit outside this page. The first is whether a bank will lend at all: investor lending is subject to loan-to-value restrictions and to servicing tests run at rates well above the advertised one. Our LVR Lending Capacity Calculator and Borrowing Capacity Calculator cover both.
The second is what the purchase does to your wider position. A single property analysed alone can look manageable while quietly pushing a portfolio past the point a bank will support. Our Property Portfolio LVR Calculator aggregates several properties into the single lending position a bank actually assesses.
Related NZ Property Investment Calculators
- Investment Property Cashflow Calculator: a longer-form cash flow view of a single rental.
- Cash-on-Cash Return Calculator: the return on the cash you actually invested.
- Cap Rate Calculator: values a property from its net operating income.
- LVR Lending Capacity Calculator: whether the deposit meets the investor limit.
- Property Portfolio LVR Calculator: the same question across a whole portfolio.