Number Crunching

6 min read

Property investment calculators

New Zealand's most comprehensive suite of investment property calculators. Use these property investment calculators to calculate your interest-only mortgage repayments, rental yields, equity, LVR, capital growth, LVR, capital growth and more.


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A smart investor treats property like a business - and in business, it's all about the numbers. Use these investment property calculators to see how investing in property now could shape the path to your retirement and financial freedom.

An interest only mortgage calculator that shows you what your interest only mortgage repayments would be when using an interest only loan for your investment property.

A rental yield calculator that shows you how much your investment property will earn or cost your per year.

Leverage is your friend and will propel you forward faster to get you to retirement earlier. Use our equity calculator to do some basic numbers to see how much your deposit or equity could allow you to invest.

This fast, simple and clear LVR Calculator will show you the LVR of your property, along with what you can potentially borrow against it.

Let’s do some basic numbers using our capital growth calculator to see how much capital growth you can achieve from your investment.

The property investment calculator, shown above, gives you the 7 key numbers you need to know when analysing a potential investment, forecast over 10 years.

It's essential to recognise that the numbers shown in this property investment calculator are averages only. The figures shown will not be the same every single week that you hold the property.

However, knowing these averages will give you the confidence to hold over time.

To make the property investment calculator simple to use, we've included assumptions about the investment, like:

  • That the purchase price of the property is the same as the value of the property. This may not always be the case. For instance, if you can purchase a property for less than its registered valuation.
  • That the mortgage used to secure the property will be interest only, rather than principal and interest. This will decrease the mortgage repayment and improve the cash flow position of the property.
  • That the interest rate on the mortgage is 4%
  • That there will be $3,500 of set-up costs. This would be spread across legal expenses, a valuation and a chattel valuationThat rates will be 0.48% of the property's value in the first year (increasing at the rate of inflation), and that insurance will cost 0.3% of the property's value in the first year
  • That a property manager will be used and will cost 7% +GST of the rent
  • That you will use a property investment accountant, who will charge $1000+GST in the first year
  • That the property will have 3 weeks vacancy per year, which means that you will only receive rent for 49 weeks in the year. This is a conservative assumption. The effect of this is that you will see a more negative picture in the figures than may actually be the case
  • Inflation is at 2% per year, which means that the rent and non-mortgage expenses will increase at 2% per year

Use this useable equity calculator to figure out how much you can borrow against your property portfolio.

A mortgage calculator that shows you what your mortgage repayments would be when using a principal and interest loan for your investment property.

This retirement calculator will help you estimate whether your current savings plan will be sufficient enough to fund your retirement lifestyle you want.

Use this cashflow calculator to work out the amount you need to top up your property each week. 

Use this debt-to-income calculator to find out how much you can borrow under the new DTI rules for your next investment property.

Considering an investment in property? Use this calculator to figure out what your return on equity will be on that investment.

Opes Partners
Ed solo

Ed McKnight

Our Resident Economist, with a GradDipEcon and over five years at Opes Partners, is a trusted contributor to NZ Property Investor, Informed Investor, Stuff, Business Desk, and OneRoof.

Ed, our Resident Economist, is equipped with a GradDipEcon, a GradCertStratMgmt, BMus, and over five years of experience as Opes Partners' economist. His expertise in economics has led him to contribute articles to reputable publications like NZ Property Investor, Informed Investor, OneRoof, Stuff, and Business Desk. You might have also seen him share his insights on television programs such as The Project and Breakfast.

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