UK Pension Calculator — How Long Will My Pension Last?

Q: How long will my pension last in retirement?

At a 4% withdrawal rate a pot is designed to last roughly 30 years. The honest answer is a probability rather than a duration: it depends on your asset mix, what returns actually arrive and in what order, and how fast inflation raises your spending. This calculator reports it as the percentage of 500 simulated market histories in which the money survives to your life expectancy.

Q: Can I retire at 60 with £400,000 in my pension?

£400,000 supports about £1,333 per month at a 4% withdrawal rate before the State Pension. Retiring at 60 means funding roughly 28 years, which is a long time for that pot to stretch on its own, but the State Pension is an inflation-adjusted income floor on top of it from State Pension age and changes the picture substantially.

Q: Who has the most accurate pension calculator?

No calculator predicts the future, so accuracy really means being honest about uncertainty. Tools that return a single number hide the range of outcomes. Prefer ones that show a distribution, a probability of success and a spread between good and bad markets, and that let you see and change every assumption.

Q: How much do I need to retire?

A common rule of thumb is 25 times your annual spending, which is the 4% rule stated backwards. If you spend £30,000 a year that is £750,000. Spending is the input that matters most because it sets both the target and the withdrawal.

Q: Does this pension calculator include the State Pension?

Not yet. Every figure comes from your own workplace pension, SIPP and ISA savings, so the results are conservative. The State Pension is an inflation-adjusted income floor on top from State Pension age and covers a meaningful share of retirement spending for most households.

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Plan Your Retirement Journey

Project your workplace pension, SIPP and ISA to your retirement date, estimate the income they'd support at a safe withdrawal rate, and stress-test the plan against market randomness with a Monte Carlo simulation.

Inflation

Withdrawal

Life expectancy

yrs

Monthly Retirement Income

£0

As 4% from £0

At age 65

Expenses

M Y

Total Corpus

£0

Account Projected value

Workplace Pension —

SIPP —

Stocks & Shares ISA —

GIA —

Total —

Pension Calculator: How Long Will My Pension Last?

This calculator projects your workplace pension, SIPP and ISA to your retirement date, then answers the question that actually matters: how long the money lasts once you stop earning. It runs 500 Monte Carlo simulations rather than a single straight-line projection, so you get the odds your pension outlives you instead of one falsely precise number.

What makes this different

500 simulated market histories, not one average. Most "how long will my pension last" calculators apply a fixed return every year. This one varies returns the way markets actually do, and reports the share of outcomes where your pot survives.

Risk lives in your investments, not your account type. A workplace pension and a GIA holding the same index funds grow identically, so the return comes from your stock/bond mix — Conservative, Moderate or Aggressive — and the simulation draws bond-like variance on the bond slice and equity-like variance on the equity slice.

Employer contributions are counted. For most people it's the single biggest lever in the plan, and it's a separate contribution stream from your own budget.

Annual Allowance and ISA limits are built in. Contribution fields flag when you exceed the 2026/27 £60,000 pension Annual Allowance or the £20,000 ISA allowance, and the budget splitter fills tax-advantaged wrappers before the taxable GIA.

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Frequently asked questions

How long will my pension last in retirement?

At a 4% withdrawal rate, a pot is designed to last roughly 30 years — that's where the number comes from. But the honest answer is a probability, not a duration: it depends on what you're invested in, what returns actually arrive and in what order, and how fast inflation raises your spending. This calculator reports it as the percentage of 500 simulated market histories in which your money survives to your life expectancy.

Can I retire at 60 with £400,000 in my pension?

£400,000 supports about £1,333/month at a 4% withdrawal rate before the State Pension. Retiring at 60 means funding roughly 28 years, which is a long time for that pot to stretch on its own — but the State Pension, paid from State Pension age (currently 66, rising to 67 and then 68), is an inflation-adjusted income floor on top of it and changes the picture substantially.

Who has the most accurate pension calculator?

No calculator predicts the future, so "accurate" really means honest about uncertainty. Tools that return one number are the least honest, because they hide the range of outcomes. Prefer ones that show a distribution — a probability of success and a spread between good and bad markets — and that let you see and change every assumption behind the answer.

How much do I need to retire?

A common rule of thumb is 25× your annual spending, which is the 4% rule stated backwards. If you spend £30,000 a year, that's £750,000. Spending is the input that matters most — it sets both the target and the withdrawal — which is why this planner asks for your expenses in the FIRE section rather than assuming a percentage of salary.

Does this include the State Pension?

Not yet. Every figure here comes from your own workplace pension, SIPP and ISA savings, so treat the results as conservative — the State Pension is an inflation-adjusted income floor on top from State Pension age, and for most households it covers a meaningful share of retirement spending. Check your forecast at gov.uk/check-state-pension.

What return and inflation assumptions does it use?

Returns come from your allocation: UK stocks 7.5%, global stocks 9%, bonds 4% and cash 3% nominal, with volatility of 17%, 19%, 6% and 1% respectively. Inflation defaults to 2.5% and the withdrawal rate to 4%. All of them are editable — these are long-run averages, not forecasts, and your results should be read as a range rather than a prediction.

Estimates only, not tax, investment or pension advice. Results depend entirely on assumptions that will not match the future exactly. Consult a licensed financial adviser before acting.