Portfolio Longevity
Calculator

Inputs

Years until the portfolio is depleted
30.998912

Results

Years until the portfolio is depleted
30.998912
Withdrawal rate at retirement (%)
5
First year investment growth
24,000

Retirement planning results

Years until the portfolio is depleted30.998912
Withdrawal rate at retirement (%)5
First year investment growth24,000

formula-map diagram

Years until the portfolio is depleted
30.998912
Withdrawal rate at retirement (%)
5
First year investment growth
24,000

Retirement planning relationship

Formula

n = -ln(1 - P × r ÷ W) ÷ ln(1 + r)

= 30.998912756564

Note

This is not financial advice. It is a simplified model: it applies the displayed standard formula to the figures you entered, assumes a single constant rate for every year, and ignores taxes, fees, sequence-of-returns risk, health costs, longevity risk and any country's specific pension, benefit or minimum-distribution rules. Real returns can be negative and real retirements rarely follow a smooth curve. Check the assumptions and consult a licensed adviser before acting on any figure.

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Frequently asked questions

What does portfolio longevity actually estimate?+

It estimates how many years your savings could last given a starting balance, an assumed rate of return, and a fixed or inflation-adjusted withdrawal amount. It is a projection based on constant assumptions, not a forecast of actual market behavior.

Why can two people with the same balance get very different longevity results?+

Longevity is extremely sensitive to withdrawal rate and assumed return: a small increase in spending or a small drop in expected return can cut years off the result, sometimes dramatically. This sensitivity is why stress-testing several scenarios matters more than trusting one number.

What is 'sequence of returns risk' and why does it matter here?+

It's the risk that poor investment returns early in retirement do outsized damage, because withdrawals during a downturn lock in losses that a portfolio can't recover from later, even if average returns end up fine over time. A simple longevity calculator using one average return rate doesn't capture this risk directly.

Does the result mean my money runs out to exactly zero at that year?+

Essentially yes, under the model's assumptions — it finds the point where withdrawals exceed the remaining balance. In reality, few retirees mechanically spend a fixed schedule to zero; most adjust spending as their balance and circumstances change.

Should I plan for the average result or a worse-case scenario?+

Most planners suggest targeting a horizon somewhat longer than your expected lifespan (e.g. to age 90-95) and testing a lower-than-average return assumption, since underestimating longevity is far riskier than overestimating it.