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FIRE Number Calculator

Find your financial independence number, see how many years until you reach it, and compare Lean FIRE, your number, and Fat FIRE side by side.

🔥 FIRE number 📈 Years to FIRE ⚖️ Lean vs Fat FIRE 🎯 Withdrawal rate
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Your starting point
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Your savings rate
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7% is a common long-term average for a stock-heavy portfolio; use a lower rate to be more conservative.
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Your FIRE target
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4% is the traditional starting point; many early retirees use 3-3.5% given longer time horizons. See our 4% rule explainer.
Your FIRE number
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FIRE number needed
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Years to FIRE
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Projected FIRE age
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Progress toward your FIRE number
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Lean FIRE vs your number vs Fat FIRE
ScenarioFIRE numberYears to reach
See Lean FIRE vs Fat FIRE for what each lifestyle actually looks like.
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Projected balance on the way to FIRE

Disclaimer: Estimates only, based on the assumptions you enter. Actual investment returns and spending will vary, and this calculator does not model market volatility, sequence-of-returns risk, or healthcare cost changes. For informational purposes only — not financial advice. Consult a financial professional for personalized guidance.

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How to use the FIRE Number Calculator
1
Enter your age and current invested assets
Include all brokerage, retirement, and investment accounts combined — not cash savings or home equity.
2
Add your monthly investment contribution
This is what drives how quickly your projected balance grows toward your FIRE number.
3
Enter your desired annual spending
In today's dollars, including a realistic healthcare budget if you plan to retire before 65.
4
Compare Lean FIRE, your number, and Fat FIRE
See how the years-to-FIRE changes across spending levels before committing to a target lifestyle.
💡 Pro tip: If you plan to retire before 65, budget for health insurance before Medicare eligibility — see our healthcare bridge guide for the main options.
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FIRE calculator FAQs
Your FIRE number is the portfolio size needed to sustain your desired annual spending indefinitely, calculated by dividing your annual spending by your chosen withdrawal rate (commonly 4%, which is the same as multiplying spending by 25).
Lean FIRE typically targets annual spending under $40,000 and a smaller portfolio, while Fat FIRE targets $80,000-$120,000 or more in annual spending and a correspondingly larger portfolio. Both use the same underlying withdrawal-rate math, just applied to a different lifestyle.
4% is the traditional starting point based on the Trinity Study, designed for a 30-year retirement. Because early retirees often face 40- to 50-year time horizons, many use a more conservative 3% to 3.5% withdrawal rate instead, which requires a larger portfolio for the same spending.
Not separately — healthcare should be included in your annual spending estimate. Early retirees typically need to budget an extra line item for health insurance premiums before Medicare eligibility at 65, since this is one of the most commonly underestimated costs in early retirement planning.
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Not sure which FIRE variant fits your lifestyle? See Lean FIRE vs Fat FIRE or Barista FIRE explained.

Related guides:

How This FIRE Number Calculator Works

This calculator divides your desired annual retirement spending by your chosen withdrawal rate to arrive at your FIRE number — the portfolio size needed to sustain that spending indefinitely. It then works forward from your current invested assets and monthly contribution, compounded monthly at your expected return, to estimate how many years it will take to reach that number and at what age.

Why the Withdrawal Rate Matters So Much

A lower withdrawal rate produces a larger FIRE number for the same spending, because it assumes a longer or more conservative retirement horizon. Moving from a 4% to a 3.5% withdrawal rate increases your required portfolio by about 14% — worth checking against your own risk tolerance and expected retirement length rather than defaulting to 4% automatically.

Why We Show Lean, Your Number, and Fat FIRE Together

FIRE isn't one target — it's a spectrum of lifestyles. Seeing how many years separate a Lean FIRE number from a Fat FIRE number, holding your savings rate constant, makes the real trade-off visible: a leaner lifestyle gets you there faster, but a fatter one gives you more room to live comfortably once you arrive.