FIRE — Financial Independence, Retire Early — is the movement built around a simple idea: if your investment portfolio is large enough to cover your living expenses indefinitely, you no longer have to work for money. The specific portfolio size you need is called your FIRE number.
The 4% Rule: Foundation of FIRE
The 4% rule comes from the Trinity Study, which analyzed historical stock and bond returns from 1926–1995. It found that a portfolio allocated 50–75% to stocks could sustain a 4% annual withdrawal rate for 30 years in all historical scenarios, including the Great Depression.
The math is simple: FIRE Number = Annual Expenses × 25. If you spend $50,000 per year, you need $1,250,000. If you spend $40,000, you need $1,000,000. If you can cut to $35,000, you only need $875,000.
The most powerful lever in FIRE is your savings rate, not your income. A person earning $60,000 and saving 50% will reach FIRE faster than someone earning $120,000 and saving 20%.
Calculate Your FIRE Date
FIRE Variations: Which Version Fits You?
- •Traditional FIRE: 25× expenses, 4% withdrawal, typically $1M–$2M portfolio target
- •LeanFIRE: 25× a very frugal lifestyle, often $500k–$800k. Requires significant lifestyle optimization.
- •FatFIRE: 25× a generous lifestyle ($80k+/year). Typically requires $2M+ portfolio and high income.
- •BaristaFIRE: Semi-retirement — portfolio covers most expenses, part-time work covers the rest (often for health insurance).
- •CoastFIRE: Invest aggressively early, then stop contributing and let compound growth do the work while you earn just enough to cover current expenses.
The Savings Rate Is Everything
At a 10% savings rate, it takes roughly 43 years to reach FIRE. At 25%, it takes about 31 years. At 50%, about 17 years. At 75%, just 7 years. This is why high earners who also live frugally can retire in their 30s.
Even increasing your savings rate by 5% can reduce your working years by 3–5 years. Run the numbers in the retirement calculator above and adjust the "monthly contribution" slider to see the impact.
Risks to Plan For
- 1.Sequence of returns risk: a major market crash in your first 5 years of retirement can be devastating — consider a cash buffer or flexible spending
- 2.Healthcare costs before Medicare eligibility at 65 — often $500–$1,500/month for individuals
- 3.Inflation eroding purchasing power over a 40–50 year retirement
- 4.Lifestyle creep — your 'enough' number can grow as you earn more; revisit it regularly
- 5.Consider a 3.5% withdrawal rate for longer retirements (40+ years)
Frequently Asked Questions
How do I calculate my FIRE number?
Your FIRE number = annual expenses × 25. This uses the 4% safe withdrawal rate. If you spend $60,000/year, your FIRE number is $1.5 million. To be conservative, some early retirees use × 30 (3.3% withdrawal rate) since they may have 40–50 year retirements. Subtract any guaranteed income (pension, rental income) before multiplying.
Build your FIRE plan →How long does it take to reach FIRE?
It depends almost entirely on your savings rate. At a 10% savings rate, it takes ~40 years. At 25%, ~32 years. At 50%, ~17 years. At 70%, ~8.5 years. The key insight: every dollar you don't spend today does double duty — it grows in your portfolio AND reduces how much you need to save (lowers your FIRE number).
Is the 4% rule safe for early retirees with 40+ year retirements?
The original Trinity Study tested 30-year retirements. For 40–50 year retirements, research suggests a 3.5% withdrawal rate is safer (FIRE number = expenses × 29). Sequence-of-returns risk is higher over longer timelines. Many early retirees use flexible withdrawal strategies — cutting spending in down markets rather than rigidly taking 4% every year.
What are the main FIRE variants?
Lean FIRE: minimal lifestyle, typically <$40k/year spending. Regular FIRE: typical middle-class spending (~$60–80k/year). Fat FIRE: comfortable lifestyle, $100k+/year spending. Barista FIRE: semi-retire with part-time work covering basic expenses while the portfolio grows. Coast FIRE: accumulate enough that compound growth alone will reach your full FIRE number at traditional retirement age — then stop saving aggressively.
Calculate your Coast FIRE number →What is Coast FIRE and how does it work?
Coast FIRE means you've saved enough that — without adding another dollar — compound growth will reach your full FIRE number by traditional retirement age. Once you hit your Coast number, you only need to earn enough to cover current living expenses (not save more). It's a less extreme first milestone: many people achieve it in their mid-30s.
Calculate your Coast FIRE number →