Compound Interest Calculator NZ
Estimate how a starting balance and regular monthly contributions could grow through compound returns over time.
Adjust your plan
Move the sliders or enter exact amounts.
Your estimate
Updates instantly as your numbers change.
Estimated future balance
$94,111
After 10 years at the entered return.
Estimated growth
$24,111
$70,000 comes from your balance and contributions.
How this calculator works
Compound growth means returns can earn further returns. This calculator separates your starting balance, contributions, and estimated growth so the result is easy to understand.
Important assumptions
- Returns compound monthly at a constant rate.
- Contributions are made at the end of each month.
- Tax, fees, and inflation are not included.
These results are general illustrations only and are not financial advice. Actual outcomes can differ.
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Common questions
Terms explained
- Compound interest
Compound interest is earning returns on your past returns as well as on the money you put in.
- Rule of 72
The Rule of 72 estimates how many years money takes to double: divide 72 by the yearly return.
- Real return
A real return is an investment return after inflation, which shows how much your buying power actually grew.
- Inflation
Inflation is the rise in prices over time, which means the same dollar buys less each year.
- Fund fees
Fund fees are what a fund manager charges each year, usually as a percentage of your balance plus any fixed dollar fee.
- Dollar cost averaging
Dollar cost averaging is investing a fixed amount on a regular schedule, whatever the market is doing.