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FinToolSuite
Updated May 14, 2026 · Savings · Educational use only ·

Retirement Withdrawal Rate Calculator

Years a retirement pot lasts at a given withdrawal rate and return.

Estimate how many years your retirement pot lasts using a withdrawal rate calculator with real return and inflation inputs.

What this tool does

Years a retirement pot lasts at constant-real withdrawals depend on the real return rate (return minus inflation). This calculator takes your starting pot value, annual withdrawal amount, and expected real annual return, then estimates how many years those withdrawals can be sustained. The result shows the longevity of your retirement savings under the stated conditions. The pot value and withdrawal amount are the primary drivers—larger pots extend the timeframe, while bigger withdrawals shorten it. Real return also matters significantly; higher returns stretch the pot further. A typical use case involves testing whether a retirement plan remains viable across different market conditions. The calculator assumes withdrawals occur at year-end, remain constant in real terms, and that returns stay consistent. It does not account for taxes, fees, or changes in spending patterns over time. Results are for illustration only.


Enter Values

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Formula Used
Pot value
Annual withdrawal
Real return rate (entered as a percentage value)

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

A 500,000 pot with 25,000 annual withdrawal at a 3% real return lasts roughly 31 years. Stretch the withdrawal to 30,000 and it lasts about 23 years. Cut it to 20,000 and it lasts past 40 years. Small withdrawal changes produce large longevity changes — a reason to be conservative with drawdown rates.

How to use it

Enter pot size, annual withdrawal in today's units, and expected real annual return (nominal minus inflation). A 3% real return is typical for diversified retirement portfolios.

What the result means

Primary is years the pot lasts. Secondary shows withdrawal as percent of pot (the implied rate), annual withdrawal in today's units, and pot size. Compare years to expected remaining lifetime — if years is below expected lifespan, the plan needs adjusting.

Limitations

Constant-return assumption ignores sequence risk — bad returns early can blow up a plan that 'should' have lasted. For formal retirement planning, combine this output with a stochastic simulation (Monte Carlo) via a financial planner.

Run it with sensible defaults

Using pot value of 500,000, annual withdrawal of 25,000, real annual return of 3%, the calculation works out to 31 years. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Pot Value, Annual Withdrawal, and Real 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

Solves the annuity-present-value equation for the number of years, assuming end-of-year withdrawals and constant-real returns. If withdrawal × (1 + return / return rate) exceeds pot, the pot never depletes — tool returns 'Indefinite'.

Turning the result into a plan

A projection is just a starting point. The real work is setting the monthly amount aside automatically so the saving happens before you can spend it. Most people who hit savings goals set up a standing order on payday; most who miss them rely on willpower at month-end.

Example Scenario

At a £25,000 annual withdrawal with 3 real return, your £500,000 retirement pot lasts approximately 31 years years.

Inputs

Pot Value:£500,000
Annual Withdrawal:£25,000
Real Annual Return:3
Expected Result31 years

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

The calculator solves the annuity present-value equation to determine how many years a retirement pot sustains a given withdrawal amount. It assumes end-of-year withdrawals, a constant real annual return applied throughout the withdrawal period, and no fees or tax deductions. The computation applies logarithms to invert the standard annuity formula, using the pot value, annual withdrawal amount, and real return rate as inputs. If the annual withdrawal multiplied by the inverse of the return rate exceeds the initial pot value, the withdrawals theoretically never deplete the capital—in this case the calculator returns "Indefinite." The model treats returns as smooth and consistent; it does not account for volatility, sequence-of-returns risk, inflation variance, taxes, or changing withdrawal amounts.

Frequently Asked Questions

Why use real return not nominal?
Because withdrawals need to rise with inflation to preserve purchasing power. Using real return means you can enter today's-pound withdrawal and get a realistic longevity estimate.
What's a safe real return for planning?
2-3% for conservative portfolios, 3-5% for balanced. Using the pre-inflation nominal return overstates longevity significantly — a common planning mistake.
How does this relate to the 4% rule?
The 4% rule implies roughly 30-year longevity at typical real returns. Use this tool to stress-test non-standard cases — early retirement, higher withdrawal rates, or lower return assumptions.
What if sequence risk hits early?
Not modelled. A bad first few years can halve the safe withdrawal rate. For serious retirement planning use Monte Carlo simulation; this tool gives the central-case answer only.

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