Calculator

Compound growth

See what time and regular contributions can do. Enter your starting amount, a contribution and an expected return — this page runs the compounding math live, and nothing is sent anywhere.

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Weekly
Fortnightly
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Results are pre-tax projections and assume a steady average return each year — real markets go up and down. Fees, inflation and taxes are not included.

Estimated future value
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Future value
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Total contributed
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out of pocket
Investment growth
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compounding returns
Time beats timing

The longer this money stays invested, the more of the final figure is growth rather than what you put in. Starting earlier — even with the same total contribution — almost always beats waiting for the 'right' moment to invest.

How the return changes it
ScenarioReturnFuture value
Common questions

Compound interest questions, answered

How does compound interest work on investments?

Compound interest means you earn returns on your original money AND on the returns you have already earned — growth that grows. Leave your returns invested and the compounding effect accelerates over time. This calculator shows that acceleration directly: the growth line bends upward as the years roll on.

What is the difference between simple and compound interest?

Simple interest is calculated only on the original amount you put in. Compound interest is calculated on the original amount plus any returns already earned, so the pool you earn on keeps growing and growth speeds up over time. Over a long horizon that difference becomes the bulk of the total.

Is it better to invest weekly, fortnightly or monthly?

With the same money and return, more frequent contributions edge out lumpier ones by compounding slightly more often — but the gains are small. The habits that matter are investing what you can, automating your contributions, and staying invested over a long time horizon rather than timing the market.

Why does time matter more than timing in investing?

Years in the market generally count for more than perfectly timing the highs and lows. Because returns compound, starting earlier or investing steadily for longer usually beats trying to buy low and sell high, which is hard to do consistently. The comparison note on this page highlights how much of the final figure comes from time in the market.