Calculate your path to Financial Independence and early Retirement. Explore all FIRE variants — Lean, Fat, Coast, and Barista — and see how your savings rate determines when you can stop working.
Based on the Trinity Study and 25× annual expenses formula
Enter your annual expenses and current savings to see your FIRE number, and how long it will take to reach financial independence at your current savings rate.
Open FIRE Calculator →FIRE stands for Financial Independence, Retire Early. It's a lifestyle movement built around the idea that by saving an unusually high percentage of your income — typically 50–70% — you can accumulate enough wealth to live off investment returns indefinitely, decades before the traditional retirement age of 65.
The movement gained mainstream attention with the 2010 blog "Mr. Money Mustache" and has since spawned a massive community (r/financialindependence on Reddit has over 2 million members) with countless substacks, books, and podcasts. The mathematical foundation is elegant: using the 4% safe withdrawal rate from the Trinity Study, your "FIRE number" is simply 25 times your annual expenses.
The 4% rule comes from a 1998 paper by three Trinity University professors who analyzed U.S. stock and bond market data from 1926 to 1997. They found that a 60/40 stock/bond portfolio could support withdrawals of 4% of the initial balance (adjusted for inflation each year) for 30 years in 95% of historical scenarios. A 3% withdrawal rate succeeded in virtually 100% of historical 30-year periods.
For FIRE practitioners with potentially 40–50 year retirements, many use a more conservative 3.25–3.5% withdrawal rate, which corresponds to saving 28.5–31 times annual expenses rather than 25 times. The flexibility to reduce spending during market downturns also significantly improves portfolio survival rates.
Lean FIRE means retiring on a minimal budget, typically under $40,000 per year for a single person or couple. Your FIRE number is $750,000–$1,000,000. Lean FIRE requires genuine frugality — it means being content with a simple lifestyle, likely avoiding expensive cities, and having very little buffer for lifestyle inflation. Many Lean FIRE practitioners live in low-cost-of-living areas, travel hack, grow food, or move to countries with lower costs. The upside: you can reach FIRE dramatically faster by both saving more and needing less.
Fat FIRE means retiring with an abundant lifestyle — typically $100,000+ per year. Your FIRE number is $2,500,000 or more. Fat FIRE requires either very high income (software engineers, doctors, lawyers, executives), long accumulation periods, or both. The upside is obvious: flexibility, comfort, and minimal financial anxiety in retirement. Fat FIRE practitioners often have significant net worth from equity compensation, business exits, or real estate in addition to market investments.
Coast FIRE is a milestone worth celebrating on the way to full FIRE. You've Coast FIRE'd when your current investments, left untouched, will grow to your full FIRE number by age 65 (or whatever your target retirement age is) with no additional contributions. At that point, you can dramatically reduce your savings rate and take lower-paying, more fulfilling work — you just need to cover current expenses because the future is already funded. The compound interest does the rest.
Barista FIRE means semi-retiring: leaving your high-stress career and working part-time in a lower-pressure job (the name comes from working at Starbucks, which historically offered health insurance to part-time employees). Your portfolio covers most expenses, and your part-time income covers the remainder — including potentially healthcare. This hybrid approach lets you exit the rat race earlier without needing the full FIRE number, and it keeps you socially engaged and active.
The savings rate is not just important — it's the dominant variable that determines your timeline to financial independence. Here's why it's so powerful: increasing your savings rate simultaneously makes you accumulate wealth faster AND means you need less wealth to retire (because you're living on less). These effects compound multiplicatively.
Approximate years to FI at different savings rates (assuming 7% real investment returns): 10% savings rate = ~43 years. 25% savings rate = ~32 years. 40% savings rate = ~22 years. 50% savings rate = ~17 years. 60% savings rate = ~12.5 years. 70% savings rate = ~8.5 years. 75% savings rate = ~7 years. Moving from a 10% to a 50% savings rate cuts your working years by more than half.
Many FIRE practitioners discover that the practical financial planning is easier than they expected, but the psychological transition is harder. Humans are wired for purpose, contribution, and social connection — things that structured work often provides (even if the work itself is unpleasant). Early retirees who thrive typically have a strong answer to "what am I retiring TO?" — not just "what am I retiring FROM?" Common paths include entrepreneurship, creative projects, volunteering, traveling, outdoor pursuits, and community involvement.
FIRE Number = Annual Expenses × 25 (using the 4% rule). $50K/year = $1.25M. For 40+ year retirements, use a more conservative 3.5% rate: Annual Expenses × 28.5. Use our calculator to factor in current savings, investment returns, and inflation.
Lean FIRE: retire on under $40K/yr ($750K–$1M needed). Fat FIRE: retire on $100K+/yr ($2.5M+ needed). Coast FIRE: saved enough that compound growth alone reaches your FIRE number by traditional retirement age — no more contributions needed. Barista FIRE: semi-retire with part-time work covering current expenses.
Savings rate is the most powerful variable. At 10%: ~43 years to FI. At 50%: ~17 years. At 70%: ~8.5 years. Higher savings simultaneously means faster wealth accumulation AND you need less wealth (because you live on less). These effects are multiplicative, not additive.
Key risks: sequence of returns (market crash early in retirement), inflation eroding purchasing power, longevity (outliving your portfolio), healthcare costs before Medicare, and the psychological challenge of finding purpose outside traditional work. Dynamic spending rules and geographic flexibility help mitigate these risks.