Regular vs Lump Sum Calculator NZ

This calculator helps you decide whether to invest a lump sum straight away or drip-feed it into the market gradually, a common dilemma after an inheritance, house sale or bonus. You enter the amount you have to invest, your expected annual return, how many months you would spread the drip-feed over, and the total number of years you plan to stay invested. The calculator then projects both approaches to the end of that period and shows you the projected value of investing the lump sum immediately, the projected value of drip-feeding it in over your chosen spreading period, and the dollar difference between the two, along with a plain-language verdict on which comes out ahead. Because the model assumes a steady rate of return, the lump sum almost always wins on paper, since more of your money spends longer in the market. What the numbers cannot show is the emotional and timing risk of investing everything the day before a downturn, which is the real reason many people choose to drip-feed despite the lower expected outcome. Use the tool to see roughly what that peace of mind is likely to cost you in New Zealand dollar terms, then weigh it against your own tolerance for a rocky start. Real returns vary year to year and are never guaranteed, so treat the results as an indicative estimate only, not financial advice.

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Investing the lump sum sooner comes out ahead
projected outcome over the full period
Lump sum now$118,029
Drip-fed in$116,807
Difference$1,222

This assumes a steady return, so the lump sum, being invested longer, comes out ahead on average. In real markets, drip-feeding reduces the risk of bad timing at the cost of some expected return. Returns are not guaranteed. Estimate only, not financial advice.

How it works

The calculator grows the whole lump sum at your expected return for the full period. For the drip-feed, it invests the amount in equal monthly instalments over your chosen spreading period, with each instalment growing only from the month it is invested to the end. Because the lump sum is fully invested sooner, it has more time in the market and so a higher projected value under a steady return, illustrating the trade-off against the lower timing risk of easing in.

Worked example

Investing $60,000 at a 7% return over 10 years grows to about $118,000 as a lump sum. Drip-feeding it over the first 12 months delays part of the investment, so it grows to slightly less, about $117,000. The gap of around $1,200 is the cost of the extra timing comfort.

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Frequently asked questions

Is it better to invest a lump sum or spread it out?

On average, investing a lump sum sooner gives a higher expected return because the money is in the market longer. Spreading it out reduces the risk of buying right before a fall, at the cost of some expected return.

What is drip-feeding?

Drip-feeding means investing the lump sum in equal instalments over a period rather than all at once, which smooths the entry price and the emotional risk of bad timing.

Which should I choose?

If you can tolerate the risk, investing sooner usually wins on average. If a sharp fall soon after would worry you out of the market, drip-feeding can be the more comfortable choice.