Dollar-Cost Averaging Calculator

This calculator projects the outcome of investing a fixed amount at regular intervals in New Zealand, the dollar-cost averaging approach that spreads your buying across market ups and downs instead of trying to time the perfect moment. You enter your regular contribution, choose how often you invest (weekly, fortnightly or monthly), set an expected annual return, and enter the number of years you plan to keep investing. The calculator then projects your final balance and splits it into two figures: the total you contributed yourself, and the growth earned on top from compounding over time. Because dollar-cost averaging means you buy more units when prices are low and fewer when prices are high, it smooths your average purchase price and removes the temptation to guess when to invest, which is why it suits most everyday investors. Use the result to compare different contribution amounts, frequencies or timeframes, and to see how the share of growth in your final balance grows the longer you keep investing, since compounding does more of the work over longer periods. Real markets rise and fall rather than growing at a steady rate, and the figures shown are before tax and not guaranteed, so treat the projection as an indicative estimate for planning rather than a promised return, and pick a regular contribution you can comfortably maintain through weaker markets as well as strong ones.

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projected balance from regular investing
Total contributed$0
Growth earned$0

Returns are assumed steady for the projection, while real markets rise and fall, which is exactly why regular investing helps. Figures are before tax and not guaranteed. Choose a contribution you can keep up through downturns. Estimate only, not financial advice.

How it works

The calculator adds your contribution at each interval and grows the balance at your expected return, compounding over the years. It then splits the final balance into the money you put in and the growth earned on top. In real life, investing the same amount regularly means you buy more units when prices are low and fewer when high, which smooths your average price and removes the temptation to time the market.

Worked example

Investing $500 a month for 20 years at a 7% return builds to around $260,000, of which $120,000 is your contributions and roughly $140,000 is growth. The longer you keep going, the more growth outweighs contributions, thanks to compounding.

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