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Financial Independence, Retire Early
FIRE calculator
Find your FIRE number, projected years to financial independence, and which FIRE flavor — Lean, Fat, or Coast — fits your numbers. Free, no sign-up.
The FIRE formula
FIRE number = 25 × annual expenses Years to FIRE ≈ ln(1 + (FIRE × r) / (12 × PMT)) / ln(1 + r) Where: r = annual real return (e.g., 0.07 for 7%) PMT = monthly savings
Types of FIRE
| Flavor | Annual spending | FIRE number | Notes |
|---|---|---|---|
| Lean FIRE | <$40k | <$1.0M | Frugal living, geo-arbitrage |
| Regular FIRE | $40k–$100k | $1.0M–$2.5M | Standard middle-class FIRE |
| Fat FIRE | >$100k | >$2.5M | Comfortable / luxury retirement |
| Coast FIRE | Cover today only | Less, but invested early | No more retirement contributions needed |
| Barista FIRE | Part-time job covers gap | ~50% of FIRE | Health insurance via part-time work |
Savings rate vs years to FIRE
From Mr. Money Mustache's classic table — assuming 5% real returns and a 4% SWR, starting from zero:
- 15% savings rate: 43 years
- 25% savings rate: 32 years
- 40% savings rate: 22 years
- 50% savings rate: 17 years
- 65% savings rate: 10.5 years
- 75% savings rate: 7 years
- 85% savings rate: 4 years
Coast FIRE explained
Coast FIRE = invest enough early that compound growth alone hits your FIRE number by age 65. After Coast FIRE you only need to cover current expenses; you never need to save for retirement again. Coast FIRE number = FIRE number ÷ (1 + r)^(65 − current_age).
Example: 30-year-old wanting $1.5M at 65 with 7% real return needs $1.5M / 1.07^35 ≈ $140,500 invested today to coast.
FIRE calculator FAQ
What is FIRE?
FIRE stands for Financial Independence, Retire Early. The movement promotes high savings rates (40–70% of income) invested in low-cost index funds, with the goal of accumulating 25× annual expenses so you can live off a 4% withdrawal rate indefinitely.
What's my FIRE number?
Your FIRE number is 25× your annual expenses. If you spend $40,000/year, your FIRE number is $1,000,000. If you spend $80,000/year, it's $2,000,000. This is based on the 4% safe withdrawal rate from the Trinity Study.
What's the difference between Lean FIRE, Fat FIRE, and Coast FIRE?
Lean FIRE is retiring on under $40,000/year of spending. Fat FIRE is retiring on over $100,000/year. Coast FIRE is having enough invested so that, without adding another dollar, compounding alone reaches your full FIRE number by traditional retirement age — you can 'coast' by covering current expenses only.
How fast can I reach FIRE?
At a 50% savings rate with 7% real returns, you reach FIRE in about 17 years from a $0 start — regardless of income level. At 65%, ~11 years. At 75%, ~7 years. Savings rate is the single biggest lever; income matters less than people think.
Is the 4% rule still safe?
Bengen's original 4% safe withdrawal rate had ~95% success over 30 years. For 40–50 year retirements (typical for FIRE), most planners suggest 3.25–3.5% to add a safety margin, plus flexibility to reduce spending in bad years.