FIRE Number Sensitivity Analyzer — Stress-Test Your Retirement Number

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Sensitivity Analyzer

FIRE Number Sensitivity Analyzer

Tweak your withdrawal rate, expenses, or return assumptions and watch how dramatically your FIRE number and timeline shift.

Your Baseline Assumptions

Current Age

Current Savings

Annual Expenses

Annual Savings

Withdrawal Rate 4.0%

Expected Annual Return 7.0%

Variance Range (± from baseline)

Expense Variance ± 20%

Withdrawal Rate Variance ± 1.0%

Return Rate Variance ± 2.0%

Three Scenarios

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Pessimistic

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⚖️

Baseline

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☀️

Optimistic

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Yrs to FIRE

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Yrs to FIRE

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Yrs to FIRE

Impact of Each Variable on Your FIRE Number

Each bar shows how much your FIRE number swings when that single variable moves to its pessimistic (left) or optimistic (right) bound. Bigger bars = higher leverage.

Portfolio Growth Across Scenarios

Biggest Lever —

FIRE Number Sensitivity Analyzer

The FIRE Number Sensitivity Analyzer lets users stress-test their retirement assumptions by adjusting variance ranges on three key variables (annual expenses, withdrawal rate, and expected returns), then seeing three side-by-side scenarios of Pessimistic, Baseline, and Optimistic update live with distinct FIRE numbers and timelines. A tornado chart ranks each variable's dollar impact so users can instantly see which lever moves their target the most, while a triple-path growth chart overlays all three trajectories against the baseline FIRE target line. The dynamic "Biggest Lever" insight names the highest-leverage variable and reframes the takeaway: expenses are dollar-for-dollar control, withdrawal rate is a safety-vs-size tradeoff, and returns are the one you can't actually control, turning abstract sensitivity data into a concrete next action.