A backtest, not a forecast

When can I retire?

Enter what you've saved and what retirement costs, and see how a plan like yours would have fared against more than a century of market history — not a forecast, a backtest.

Try it with your numbers↓

About you

Your age today — the simulation starts here.

What you've saved

Pre-filled with an average UK split (ONS/HMRC) — adjust to your actual holdings.

What you save monthly (optional)

Defaults to pension — expand to split out ISA contributions.

Fine-tune

The total to spend each year in retirement, in today's money.

Not sure? See typical spending levels

The Pensions UK Retirement Living Standards describe three illustrative single-person lifestyles. These are yearly spending figures (not income) and assume your home is owned outright. Pick one as a starting point — you can change it.

Source: Pensions UK Retirement Living Standards
How long your money should last.
Why this is past your life expectancy

It's a planning horizon, not a prediction. The default sits near the age only about 1 in 4 people reach, so a plan isn't funded just to average life expectancy and left to run out early. Grounded in ONS longevity data — see How it works.

Equity allocation: 60% equities / 40% bonds

How your invested money is split between shares (equities) and bonds — not property or home equity.
What the trade-off means

More in shares has historically grown more over the long run but swung harder along the way; more in bonds was steadier but lower. The same mix applies to your ISA and pension pots.

60% is an illustrative starting point, not a recommended allocation.

Yearly investment charges, as a percentage of your invested pots.

The annual State Pension figure to model, in today's money.

The age your State Pension starts paying.

The earliest age you can draw your pension.

Your results appear here

Fill in your plan and press “See when you could retire”.

The results show your earliest retirement age, how often the plan survived history, and a chart of how the balance could range.

How it works

  1. Enter what you've saved, what you add each month, and what retirement spending looks like per year.
  2. The plan is replayed against every full-length period of market history since 1871 — each starting year is one cohort.
  3. The result is the earliest retirement age at which the plan survived at least 90% of those historical periods, with a chart of how balances ranged.

The method, in plain English

Backtesting, not forecasting. The tool makes no prediction about future markets. It asks a narrower, checkable question: if this plan had started in 1871, in 1872, in 1929, in 1975 — every year history allows — how often would the money have lasted? Each of those replays is a cohort: the same plan walked through the actual sequence of returns and inflation that began in that year.

What the bands mean.The chart's solid line is the median balance across all cohorts at each age. The shaded bands around it show where the middle 50% of cohorts landed (“Likely”), the middle 80% (“Less likely”), and the full range from the single best to the single worst cohort (“Rare”).

Why 90% is the bar. An age counts as feasible when the plan survived at least 90% of historical periods. A 100% bar would let the very worst stretches of the past — and only those — decide every answer; a lower bar would call plans feasible that failed often. Surviving 90% of history is a strict test that still reflects the broad sweep of the record rather than its single worst path.

Why the plan-to age defaults to 93. This is an illustrative starting point, not a target. Office for National Statistics (ONS) cohort projections give a 65-year-old roughly a 1-in-4 chance of reaching about 92 (men) or 94+ (women) — the 93 default is the average of those two figures. The presets 92 and 94 let you align to the ONS figures if relevant. A common planning convention is to fund to around that 1-in-4 survival age rather than average life expectancy. Sources: the ONS life expectancy calculator, the ONS national life tables 2022–24, and ONS health-state life expectancies by deprivation decile.

Where the data comes from.Bond, cash, inflation, and exchange-rate series are from the Bank of England's “A Millennium of Macroeconomic Data for the UK” (v3.1, Thomas & Dimsdale). Contains public sector information licensed under the Open Government Licence v3.0. Equity returns are US stock-market returns — the S&P Composite with dividends reinvested, from Robert J. Shiller's “Stock Market Data Used in Irrational Exuberance” (shillerdata.com) — converted to sterling and adjusted for UK inflation: what a UK investor holding US equities unhedged would have experienced. No openly licensed UK equity total-return series covers the full period, so the tool uses the US series rather than a shorter or proprietary UK one. Coverage is 1871–2016 throughout.