What Is FIRE?
FIRE — Financial Independence, Retire Early — is a framework for ending wage dependence as early as possible by saving aggressively and investing in broad-market assets. The core mechanic: once your portfolio is large enough that a safe withdrawal rate covers your annual expenses, you're financially independent. Work becomes optional.
The 4% Rule Explained
The famous "4% rule" comes from the 1998 Trinity Study, which back-tested US stock/bond portfolios over rolling 30-year windows. It found that a 4% initial withdrawal rate (adjusted annually for inflation) had a very high historical success rate — roughly 95%+ for 50/50 or 60/40 allocations over 30 years.
Converting this to a target: if you spend $40,000/year, you need $40,000 / 0.04 = $1,000,000 — that is, 25× annual expenses. This calculator defaults to 25× but lets you set a more conservative multiplier (28×, 33×) for longer retirement horizons or Lean/Safe FIRE.
Real Returns, Not Nominal
A 30-year retirement plan denominated in today's dollars must use real returns, not nominal. The Fisher relation:
rreal = (1 + rnominal) / (1 + inflation) − 1
A 7% nominal return with 3% inflation gives a ~3.88% real return. That single adjustment can change your FIRE date by 5-10 years. All projections on this page are in real terms — both the target and the growth curve.
Monte Carlo vs Deterministic Projection
Constant-return projections are misleading because returns vary. A 7% average might mean +22%, -5%, +12%, +18%, -14%, +9% — and the order matters a lot in the withdrawal phase (sequence-of-returns risk).
Enable Monte Carlo to run 1,000 random paths using your expected return and volatility assumptions. The "Success Rate" is the percentage of paths that reach the FIRE target within the projected horizon. For a robust plan, aim for 85-95% success.
Savings Rate Is the Dominant Variable
Counterintuitive but true: your savings rate matters far more than your return. Classic Mr. Money Mustache math:
- Save 10% of income → ~51 years to FIRE
- Save 25% → ~32 years
- Save 50% → ~17 years
- Save 70% → ~8.5 years
Every 1% increase in savings rate cuts years off your FIRE date, regardless of market returns. Focus on the income-expense gap, not on squeezing extra basis points from your portfolio.
Variants of FIRE
- Lean FIRE — minimalist lifestyle, target $500K-$1M, 25-30× expenses
- Standard FIRE — ~$1M-$2.5M, 25× expenses, 4% rule
- Fat FIRE — higher lifestyle, $2.5M+, 25-33× expenses
- Coast FIRE — accumulate enough that compounding alone reaches FIRE by traditional retirement age; stop contributing
- Barista FIRE — portfolio covers most expenses; part-time work covers the rest and provides healthcare
Regional Considerations
The 4% rule is US-centric. Indonesian, Russian, and Indian savers face higher inflation and often higher returns — adjust assumptions accordingly. For example, Indonesia's multi-decade inflation has averaged ~4-5%, so a 10% nominal equity return translates to ~5% real. European savers with 2-year negative rates (2020-2022) have historically needed higher savings rates.
Limitations
This tool simplifies: constant volatility (no regime-switching), no Social Security / pension integration, no tax-account segregation (pre-tax vs Roth vs taxable), no changing expenses across life stages. For more advanced modeling, see the VaRisk Kancil platform (portfolio-level risk analytics).
Related Tools
- Compound Interest — underlying growth mechanics
- Mortgage Calculator — housing in your FIRE plan
- Loan Calculator — debt payoff strategy
- Bond YTM — fixed-income positioning