Index Fund Projection Calculator NZ

This calculator projects the long-term growth of an index fund investment in New Zealand, combining a starting sum with regular contributions and compounding them at an expected return after fees. Low-cost index funds, which track a whole market rather than trying to beat it, have become the default choice for many Kiwi investors and underpin a lot of KiwiSaver growth funds, precisely because steady contributions and the magic of compounding do the heavy lifting over time. You enter your starting balance, the amount you contribute each month, the annual return you expect, the fund's fee, and the number of years, and the calculator subtracts the fee from the return and compounds the lot monthly to show the projected future value, the total you contributed along the way, and how much of the final figure is investment growth rather than your own money. The growth portion is usually the eye-opener, because over a few decades it can dwarf the contributions. Two honest caveats apply: returns are never guaranteed and real markets lurch up and down, so treat the figure as a planning projection rather than a promise, and remember that fees compound against you, which is why even a small fee difference matters over the long haul. Use a conservative return for a sober estimate.

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projected value after fees
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Compounded monthly at the return less the fund fee. Returns vary and are not guaranteed. Estimate only, not financial advice.

How it works

The calculator takes your return, subtracts the fund fee, and compounds the net rate monthly on both the starting balance and your regular contributions. The future value is the grown starting sum plus the grown stream of contributions. Total contributed is your own money in, and growth is the rest.

Worked example

Starting with 10,000 dollars and adding 500 a month for 25 years at a net 7.5 percent (8 percent less a 0.5 percent fee) grows to several hundred thousand dollars, of which well over half is growth rather than contributions.

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Frequently asked questions

What return should I assume for an index fund?

A broad share index fund has historically returned somewhere around 7 to 10 percent a year before fees over the long run, though with big ups and downs. A conservative long-term assumption is sensible, and you should subtract the fund's fees.

Why do fees matter so much?

Fees compound against you. Even a 1 percent annual fee can cost a large share of your final balance over decades, which is why low-fee index funds are popular. The calculator subtracts the fee from the return.

Does this guarantee a return?

No. Markets are volatile and returns are never guaranteed. This is a projection based on a steady assumed return, useful for planning, not a promise of any particular outcome.