Legacy Planning Calculator

Legacy planning is the question: given current savings, spending, and expected longevity, what can realistically be left for beneficiaries? This is different from retirement planning (sustaining lifestyle) — it asks what remains after a life's financial decisions are executed.

The math uses forward projection: portfolio grows at expected return, spending reduces it. At the planning age (often 85-95), remaining portfolio is the legacy. Factors that increase legacy: lower spending rate, higher return, shorter life expectancy. Factors that decrease: higher spending, lower return, longer life (which is the goal but complicates legacy planning).

For most households, legacy is a by-product rather than a primary goal. Focus on sustaining lifestyle through retirement; legacy emerges from what remains. Planning to maximise legacy typically requires under-consumption during retirement years, which may not match values. The calculator makes visible the trade-off so the decision is conscious.

How to use it

Input current portfolio, annual spending in retirement, expected real return, current age, and planning age (often 85-95). The tool projects portfolio balance at the planning age — this is the potential legacy.

What the result means

Projected balance at planning age is the legacy available, in today's purchasing power if using real return. Negative values mean portfolio depletes before planning age — spending pace doesn't sustain to that age. Adjust spending or return assumptions to model different scenarios.

Planning tool. Legal structuring of inheritance requires qualified legal and tax advice.

Run it with sensible defaults

Using current portfolio of 500,000, annual spending of 25,000, expected real return of 4%, current age of 65, the calculation works out to 291,770.46. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Current Portfolio, Annual Spending, Expected Real Return, Current Age, and Planning Age — do not pull with equal force. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

How the math works

Iterates annual portfolio growth minus spending from current age to planning age. Uses real return for consistency with present-value spending. Balance at planning age is projected legacy.

Using this to think, not predict

Financial plans are wrong by month six — new information arrives and reshapes the picture. The point of running projections isn't to be right in ten years; it's to be less wrong in the decision you're making this week.

What this doesn't capture

Real plans get re-run against new information every year or two. The result here is a reasonable direction, not a destination. It is a starting point for thinking, not a commitment to a specific future.