FIRE Calculator
Calculate your Financial Independence, Retire Early number — see how long until you can retire based on savings rate, expenses, and investment returns. Compare Lean, Fat, and Coast FIRE.
FIRE Calculator
Your Financial Details
FIRE Results
Your FIRE Number
$1.00M
Time to FIRE: 16y 7m
Annual Savings
$40.00K
Savings Rate
50.0%
Real Return
3.88%
Coast FIRE
$326.06K
FIRE Variants
Retirement Income
Growth Projection
| Year | Balance | Growth |
|---|---|---|
| 1 | $93.50K | $3.50K |
| 2 | $140.04K | $6.55K |
| 3 | $189.85K | $9.80K |
| 4 | $243.14K | $13.29K |
| 5 | $300.16K | $17.02K |
| 10 | $651.02K | $39.97K |
| 15 | $1.14M | $72.17K |
| 17 | $1.39M | $88.42K |
| 20 | $1.83M | $117.32K |
Row highlighted = year you reach FIRE
Complete Guide to FIRE (Financial Independence, Retire Early)
What is FIRE?
FIRE stands for Financial Independence, Retire Early. It is a movement focused on aggressive saving and investing so you can stop working for money far earlier than the traditional retirement age of 65. The core idea is simple: save a large portion of your income, invest it wisely, and live off the returns.
Your FIRE number is the portfolio size that can sustain your annual expenses indefinitely through investment withdrawals. Once your investments reach this number, work becomes optional — you have achieved financial independence. Use our Compound Interest Calculator to see how compounding accelerates your path.
The FIRE Formula
FIRE Number:
FIRE Number = Annual Expenses / Withdrawal Rate
FIRE Number = Annual Expenses x 25 (at 4% SWR)
Where: SWR = Safe Withdrawal Rate (typically 4% based on the Trinity Study). At 4%, you need 25x your annual expenses.
Years to FIRE (with existing savings):
Years = ln((S + r × F) / (S + r × P₀)) / ln(1 + r)
Where: S = annual savings, r = real return rate, F = FIRE number, P₀ = current portfolio. The real return adjusts nominal returns for inflation.
FIRE Variants
Lean FIRE
Retire on a minimal budget (roughly 70% of current expenses). Requires the smallest nest egg but demands a frugal lifestyle.
Fat FIRE
Retire with a generous budget (150%+ of expenses). Larger target but allows a comfortable lifestyle without cutting back.
Coast FIRE
Save enough early so compound growth alone reaches your FIRE number by traditional retirement age — no more contributions needed.
Barista FIRE
Partially retired — work a low-stress job for benefits and spending money while investments grow. Bridges the gap to full FIRE.
Tips for Reaching FIRE Faster
Maximize savings rate: The single biggest lever is the gap between income and expenses. A 50% savings rate dramatically shortens your timeline compared to 20%. Track spending with a Savings Goal Calculator.
Invest in low-cost index funds: Broad-market index funds minimize fees and consistently outperform most active managers over decades. Check your expected growth with the Investment Calculator with Inflation.
Increase income, not lifestyle: Side hustles, career moves, and raises accelerate FIRE only if you invest the difference rather than inflating your spending.
Common Mistakes
Ignoring Inflation
A 7% nominal return with 3% inflation is only ~3.9% real growth. Always plan in real (inflation-adjusted) terms or your FIRE number will be too low. Use our Inflation Calculator to see the impact.
Underestimating Healthcare Costs
Early retirees lose employer health coverage. Factor in private insurance premiums or ACA marketplace costs — these can be thousands per year and rise faster than general inflation.
Using the 4% Rule Blindly
The 4% rule was designed for a 30-year retirement. FIRE retirements can span 40-60 years. Consider a 3.25-3.5% withdrawal rate for extra safety, or plan for flexible spending in down markets.
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OpenFrequently Asked Questions
What is FIRE (Financial Independence, Retire Early)?
FIRE is a movement focused on saving aggressively (often 50–70% of income) to build a portfolio large enough that the safe withdrawal rate covers your expenses. The goal: financial independence years or decades before traditional retirement age, giving you the freedom to stop working or pursue passions.
What is the FIRE number?
Your FIRE number = annual expenses × 25 (the 4% rule's inverse). If you spend $40,000/year, your FIRE number is $1,000,000. Withdrawing 4%/year from that portfolio statistically lasts 30+ years (Trinity Study). For longer retirements (50+ years), use 3.25–3.5% withdrawal rate, or 28–30× expenses.
What's the difference between Lean FIRE, Fat FIRE, and Coast FIRE?
Lean FIRE: minimalist lifestyle, ~$20–40K/year expenses, $500K–$1M portfolio. Fat FIRE: comfortable lifestyle, $80–200K/year expenses, $2M–$5M+ portfolio. Coast FIRE: you've saved enough that compound growth alone reaches your FIRE number by traditional retirement — you just need to cover current expenses, not save more.
Is the 4% withdrawal rule really safe?
For 30-year retirements, ~95% historically safe. For 50-year retirements (early FIRE), use 3.25–3.5% to account for sequence-of-returns risk over longer timeline. Other safety improvements: maintain flexibility (cut spending in down markets), keep 1–2 years cash buffer, work part-time during early years to reduce withdrawals.
How much do I need to save to retire early?
Depends on income and target spending. Saving 50% of take-home income → retire in ~17 years. Saving 65% → ~10 years. Saving 75% → ~7 years. (Mr Money Mustache's classic table.) The math is: years-to-retire ≈ time for portfolio to reach 25× annual expenses, given your savings rate and expected returns.
What if returns are worse than historical averages?
FIRE plans should test multiple scenarios. The 4% rule was based on the worst historical 30-year periods (Great Depression, 70s stagflation). For low-return decades, withdraw less (3–3.5%) or have a side income (geo-arbitrage, freelance) to reduce stress on the portfolio. Flexibility beats precision in real-world FIRE planning.