Historical FIRE Backtest Calculator
This page asks a hard but useful question: if the same retirement plan had started in very different market environments, how often would it actually have held up?
How To Read This
This page answers a different question than Monte Carlo. Instead of generating random futures, it replays many rolling windows from the same built-in real return series so you can see how the plan would have behaved in rough versus friendly historical-style stretches.
Backtest Windows
| Start year | End year | Outcome | Failure year | Ending value |
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Historical Backtest FAQ
What does this historical FIRE backtest show?
It shows how the same withdrawal plan would have behaved if retirement had started in many different historical-style windows. That exposes whether the plan only works in kind markets or still survives tougher start dates.
Is this the same as a Monte Carlo simulation?
No. This page replays rolling historical real return windows, while the Monte Carlo FIRE Simulator generates many random future paths from your assumptions.
What should I compare this with?
If you want to isolate early bad years versus late bad years, use the Sequence Risk Calculator. If you want a rough spending-based target first, start with the 4% Rule Calculator.
This is not financial advice. Historical backtests can reveal how little margin a plan really had, but they still cannot guarantee future outcomes.