Tiny Toolkit

FIRE Number Calculator

Calculate how much you need to retire early using the 4% rule and your annual expenses.

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Frequently Asked Questions

What is the 4% rule?
The 4% rule (also called the safe withdrawal rate) suggests you can withdraw 4% of your portfolio in year one of retirement and adjust for inflation each year, with a high probability of the portfolio lasting 30 years. It is based on historical US stock and bond returns studied by William Bengen in 1994.
How is the FIRE number calculated?
FIRE Number = Annual Expenses / Safe Withdrawal Rate. At a 4% SWR, that is Annual Expenses × 25. If you spend $60,000 per year, your FIRE number is $1,500,000. Lowering your withdrawal rate (e.g. to 3.5%) increases the required savings but improves longevity.
Is the 4% rule still valid?
It remains a widely used benchmark, though some researchers argue that current low bond yields and high valuations suggest a more conservative 3–3.5% rate for early retirees with 40+ year horizons. A higher equity allocation and flexibility to reduce spending in down markets improves the odds.
What is "lean FIRE" vs "fat FIRE"?
Lean FIRE means retiring on minimal expenses, often under $40,000 per year. Fat FIRE targets a comfortable or affluent lifestyle, typically $100,000+ per year. Barista FIRE involves retiring from full-time work but keeping a part-time job for health insurance or supplemental income.

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