About the FIRE Calculator
The FIRE Calculator computes your FIRE number (25× annual expenses, derived from the Trinity Study’s 4% safe withdrawal rate), projects the timeline to reach it from current savings + savings rate + expected real return, and renders a progress ring. Compare Lean FIRE (~$40K/yr expenses), Regular FIRE ($40–100K), and Fat FIRE ($100K+) to see how lifestyle choices reshape the timeline.
It is built for mid-career professionals running their first serious FIRE math, software engineers and other high-earners stress-testing whether they can retire by 45, dual-income households modeling Coast FIRE timelines, and skeptics wanting to see why a 50% savings rate retires you in ~17 years regardless of income level. Coast FIRE (stop contributing now, let it grow) and Barista FIRE (semi-retire with part-time work) modes are available.
All projection math runs locally in your browser. Income, expenses, current portfolio, and savings-rate inputs never leave your device. The page makes no network call after first load. Net-worth-and-spending data is among the most personally identifying financial inputs; the calculator never sees it.
The 4% rule is a planning baseline, not a guarantee. Updated Bengen 2023 research suggests 4.7% may be sustainable for typical retirements; the FIRE community often uses 3.25–3.5% for early retirees facing 50+ year horizons to account for sequence-of-returns risk and longer time exposed to bad market sequences. Healthcare costs in early retirement (pre-Medicare, age 50–65) are the most under-budgeted line in most FIRE plans — ACA subsidies help but plan for $15–25K/yr in premiums + out-of-pocket. Always pair the headline projection with a Monte Carlo simulation (cFIREsim, FICalc) before quitting.
Coast FIRE
The amount you need saved today so investment growth alone reaches your FIRE number by traditional retirement age (65) — no more contributions needed.
Barista FIRE
Model partial retirement: work part-time to cover living expenses while your investments grow untouched to your full FIRE number.
Monte Carlo Simulation
Probability of your plan succeeding across thousands of simulated historical market scenarios.
What Is the FIRE Movement? (Financial Independence Explained)
FIRE stands for Financial Independence, Retire Early. The core idea is straightforward: save and invest aggressively so that your investment portfolio generates enough passive income to cover your living expenses indefinitely. Once you reach that point — your “FIRE number” — work becomes optional rather than mandatory.
Financial independence does not require a six-figure salary. The movement emphasizes that the gap between income and spending determines timeline far more than raw earnings. Someone earning $60,000 who spends $30,000 will reach FIRE faster than someone earning $200,000 who spends $180,000, because the savings rate — not income — drives the math.
The 4% Rule: How Much Do You Need to Retire?
The 4% rule originates from the Trinity Study, which analyzed historical stock and bond market returns to determine a sustainable withdrawal rate over a 30-year retirement. The conclusion: withdrawing 4% of your portfolio in the first year of retirement, then adjusting for inflation each year, survived roughly 95% of all historical 30-year periods.
In practical terms, the 4% rule means you need 25 times your annual expenses saved and invested. If you spend $40,000 per year, your FIRE number is $1,000,000. If you spend $60,000, it becomes $1,500,000. This calculator lets you adjust the withdrawal rate up or down to match your risk tolerance and planned retirement length.
Lean FIRE vs Fat FIRE: Finding Your Number
The FIRE community recognizes several lifestyle tiers. Lean FIRE targets a minimal budget — typically 80% of current spending — and is ideal for people comfortable with frugal living. Regular FIRE maintains your current lifestyle. Fat FIRE plans for an upgraded lifestyle at roughly 150% of current expenses, giving you room for travel, hobbies, and unexpected costs without stress.
Which tier is right depends on your personality, health needs, family plans, and geographic flexibility. Many people start targeting Lean FIRE for an early escape hatch, then continue working part-time toward Regular or Fat FIRE for added security.
Why Savings Rate Matters More Than Income
The single most powerful lever in the FIRE equation is your savings rate. A higher savings rate has a dual effect: it increases the amount flowing into investments while simultaneously proving you can live on less — which lowers the FIRE number you need to reach. This double-sided benefit is why someone saving 50% of their income can reach financial independence in about 17 years, while someone saving 20% needs closer to 37 years.
Investment returns matter, but they are largely outside your control. Your savings rate is the one variable you can directly influence today. The “Savings Rate Impact” chart above illustrates this relationship clearly — experiment with different rates to see the dramatic effect on your timeline.
Coast FIRE: The Part-Time Retirement Strategy
Coast FIRE is a milestone where you have saved enough that compound growth alone will carry your portfolio to your full FIRE number by traditional retirement age, even if you never invest another dollar. Once you hit Coast FIRE, you only need to earn enough to cover current expenses — opening the door to lower-stress, part-time, or passion-driven work decades before full retirement.
A related concept is Barista FIRE, where you leave your full-time career and take part-time work (the name refers to the stereotype of working at a coffee shop for health insurance). The part-time income covers daily expenses while your invested assets grow untouched. Use the subscriber tools above to model both scenarios with your own numbers.
Looking for more financial planning tools? Try the Personal Finance calculators for compound interest, debt payoff, and budgeting tools that complement your FIRE plan.
Frequently Asked Questions
What is a FIRE number?
A FIRE number is the portfolio size needed to cover annual living expenses indefinitely from investment returns. A common approximation is 25 times annual expenses, which corresponds to a 4 percent safe withdrawal rate.
What is the 4 percent rule?
The 4 percent rule, derived from the Trinity Study, suggests that withdrawing 4 percent of a diversified portfolio in the first year of retirement and adjusting that amount for inflation each year has historically provided a high probability of lasting 30 years. Longer retirements may warrant a more conservative rate.
What is the difference between Lean FIRE, Regular FIRE, and Fat FIRE?
Lean FIRE aims for a minimalist lifestyle, often under $40,000 per year in expenses. Regular FIRE targets middle-class spending, commonly $40,000 to $100,000. Fat FIRE supports a more comfortable lifestyle with expenses above $100,000 per year, which requires a much larger portfolio.
How does savings rate affect time to FIRE?
Savings rate is the single biggest driver of time to financial independence. At a 10 percent savings rate, FIRE takes around 50 years. At 50 percent, it takes roughly 17 years. At 75 percent, it can take under 10 years. Higher savings simultaneously grows the portfolio and lowers the expenses the portfolio must cover.
Is FIRE realistic for average earners?
FIRE emphasizes savings rate over income level, so it is possible for middle-income earners, though the timeline is usually longer. Lifestyle inflation, high-cost areas, and family obligations can make aggressive savings difficult. Anyone planning toward FIRE should consider consulting a financial advisor.