Minimum lump sum needed today to hit a target by a given year at a given return.

To reach 100,000 in 15 years at a 7% return, the minimum lump sum today is roughly 36,245. At 5% the minimum rises to about 48,102; at 9% it drops to 27,454. Small rate differences have large cash impact over 10+ year horizons.

What the result means

Primary is minimum lump sum. Secondary shows the compound growth that gets it to target, the multiple on the starting amount, and the growth rate applied. Compare to what you actually have today — the difference tells you how far off the mark you are.

When this matters

Windfalls (inheritance, bonus, property sale) force the question: invest now and forget, or spread it out? This tool gives the lower bound — the minimum you need from that windfall if you want to hit a specific goal. Anything above that gives a margin of safety.

Run it with sensible defaults

Using target amount of 100,000, years of 15 years, annual return of 7%, the calculation works out to 36,244.60. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Target Amount, Years, and Annual Return — do not pull with equal force. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

How the math works

Present value of the target at the chosen return rate, annually compounded. Assumes no further contributions after the initial lump sum. For combined lump-sum-plus-monthly scenarios, use the Catch-Up Savings or Monthly Investment Goal tool. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this well

Treat the output as one point on a wider map. Run it three times — a pessimistic case, a central case, and a stretch case — and plan against the pessimistic one. That habit alone separates people who stick with an investment plan from those who bail at the first wobble.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. Treat the number as one scenario, not a forecast.