Business & dates New Zealand
ROI Calculator New Zealand
Return on investment (ROI) measures how much you made against how much you put in. This calculator takes the amount invested, the final value and any income received, and shows the total ROI, the annualised rate over the years you held it and an after-tax figure if you want one.
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Dividends, rent or interest, after costs.
Optional. Leave at 0 if the profit is not taxed.
Return on investment
—Gain
—
Per year (annualised)
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Gain after tax
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ROI after tax
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Value multiple
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The working
General information only. General information and estimates only, not financial, tax or legal advice. Rates, thresholds and rules change, so check with the Inland Revenue or a registered tax adviser before you act.
How do I calculate ROI?
Divide the gain by the amount invested. $20,000 that grew to $31,000 and paid $1,500 of income made a gain of $12,500, an ROI of 62.5%. Over 5 years that is 10.2% a year, which is the figure to compare with other investments.
Comparing investments
Different investments carry different risks, so a higher ROI is not automatically better. A term deposit's return is certain and protected by the deposit guarantee, while a share or a property can fall in value. Compare the annualised return for the same period and think about how much you could lose.
ROI can also be used for a business purchase: the gain from a new machine or advertising spend divided by what it cost.
Tax on the profit
New Zealand has no general capital gains tax, but profit can still be taxable: property sold within the bright-line period, shares bought for resale, and a share portfolio held overseas above a threshold under the foreign investment fund rules. Income such as dividends and rent is taxable.
Enter your marginal rate if the profit is taxed, or leave it at zero if it is not. Check your position with Inland Revenue or a tax adviser.
How this is calculated
The rule, step by step, so you can check any figure by hand.
gain = final value + income received − amount invested − costsROI % = gain ÷ amount invested × 100annualised return = ((final value + income − costs) ÷ amount invested)^(1 ÷ years) − 1after-tax gain = gain − tax on the profitvalue multiple = (final value + income) ÷ amount invested
ROI on its own ignores time: 50% over two years is a much better result than 50% over ten. The annualised figure turns any holding period into a comparable yearly rate, which is why the tool shows both.
Treat the annualised return as an average. It assumes the income arrives with the final value and compounds smoothly, whereas a real investment has ups and downs, and past returns do not guarantee future ones.
A worked example
$20,000 invested, worth $31,000 after 5 years, with $1,500 of income received.
- Gain$12,500
- ROI62.5%
- Value multiple1.62×
- Annualised return10.2% a year
An ROI of 62.5%, or 10.2% a year.
Compare the annualised figure with a term deposit rate to see whether the risk paid off.
Costs matter
Buying and selling costs, fees and holding costs eat into ROI, especially on short holding periods. Enter them in the costs field to see the net figure.
What it leaves out
Inflation, timing of cash flows and risk are not modelled. A return of 5% when inflation is 3% is a real return of about 2%.
What this calculator does not do
- Single investment, one period
- Income treated as arriving at the end
- Tax as a simple rate
- General information, not advice
Common questions
What is ROI?
Return on investment: the gain as a percentage of the amount invested.
What is annualised return?
The equivalent yearly rate that would produce the same total gain over the years held.
Is a higher ROI always better?
Not if it carries more risk or takes longer.
Should I include costs?
Yes. Buying, selling and holding costs reduce the return.
Does ROI include tax?
Only if you enter a tax rate.
Where these numbers come from
- Inland Revenue — tax on investments Which investment income and sales of property or shares are taxable
- business.govt.nz — running a business Government guidance on pricing, costs and starting out
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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