Fat FIRE Calculator
Find the portfolio you need to retire early without cutting back, and see the age you'll reach it at your current pace. Results update as you type.
Fat FIRE is the same division with a generous spending figure: annual spending ÷ withdrawal rate. This page ships with $100,000 of retirement spending, so at a 4% withdrawal rate the target is $2,500,000, and the Coast FIRE number, the balance that reaches it by 65 from age 30 with nothing added, is $633,539. The remaining defaults are $120,000 invested, $1,000 a month, and a 7% return against 3% inflation and 0% fees, which gives the 4% real return the projection uses. Change any of them under Advanced assumptions. The withdrawal rate comes from Bengen's 1994 paper and the Trinity Study, and how our calculators work shows the full method.
What is Fat FIRE?
Fat FIRE is financial independence on a generous budget, typically $100,000 or more in annual spending. Where Lean FIRE gets you free early by keeping costs low, Fat FIRE buys freedom and comfort: travel, a nicer home, private health cover, family support, and plenty of slack for surprises. The price is a much bigger portfolio and usually a longer accumulation phase.
How is your Fat FIRE number calculated?
Fat FIRE number = fat annual spending ÷ withdrawal rate
Enter the annual budget you actually want in retirement, not the one you could survive on. The calculator shows the portfolio that funds it indefinitely and, using your current investments, monthly contributions and real return, projects the age you'll cross it. Everything is inflation-adjusted, so figures stay in today's money.
Three levers that matter most for Fat FIRE
- Income growth beats frugality. You can't easily cut your way to a $2.5M+ target. Career moves, equity compensation and business income are what typically fund Fat FIRE.
- Time in the market. A decade of compounding does enormous work on a seven-figure target, starting five years earlier can shave more off the timeline than doubling contributions later.
- Withdrawal-rate honesty. A fat budget has more discretionary spending you can trim in bad markets, which is why many Fat FIRE plans still use 4% rather than something more conservative.
What does Fat FIRE actually cost?
The arithmetic is unforgiving because the multiplier works against you. Every extra $10,000 of annual spending adds $250,000 to the target at a 4% withdrawal rate. That is the whole story of Fat FIRE in one sentence.
Two people, ten years apart in outcome
Both are 40, both earn well, both plan to retire at 60.
A: spends $100,000/yr → target $2,500,000
B: spends $130,000/yr → target $3,250,000
The $30,000 lifestyle difference costs $750,000 of portfolio. At $4,000 a month invested and a 4% real return, that gap alone represents roughly a decade of additional saving. Fat FIRE plans live or die on the spending number, not the returns assumption.
How people actually fund it
A $2.5 million target is difficult to reach on salary and frugality alone, and pretending otherwise is where most Fat FIRE content goes wrong. In practice the money tends to come from one of a few places:
- Income growth over a long career. Compounding a high savings rate on a rising salary for twenty years is the unglamorous, most common route.
- Equity compensation. For many people in technology and finance, vesting stock does more work than the base salary ever does, with the corresponding concentration risk.
- A business sale. One liquidity event can replace a decade of saving, though the failure rate behind each success rarely makes it into the story.
- Dual high incomes with flat spending. Two earners who resist lifestyle inflation reach large numbers surprisingly fast.
What is common to all four is that the accumulation phase does the heavy lifting. Once the portfolio is large, the returns are large in absolute terms, which is why Fat FIRE plans often accelerate sharply in their final years.
Which withdrawal rate should you use at this size?
A fat budget contains more discretionary spending than a lean one, and that flexibility is genuinely worth something. A retiree spending $120,000 who could comfortably drop to $90,000 in a bad market has a built-in shock absorber that a $30,000 lean retiree simply does not have. This is why many Fat FIRE plans stay at 4% rather than dropping to 3.25%, and it is a defensible choice, provided the flexibility is real rather than theoretical.
The counterweight is horizon. Retiring at 50 on a fat budget means funding perhaps forty years, and sequence risk does not care how comfortable your budget is. A reasonable compromise many use: plan at 3.75%, keep two years of spending in cash, and treat the discretionary third of the budget as genuinely cuttable.
Frequently asked questions
How much do you need for Fat FIRE?
The common threshold is $100,000+ of annual spending, which at 4% means $2.5 million invested. Couples in high-cost cities often target $150-200k of spending, $3.75-5 million.
Fat FIRE vs Chubby FIRE?
"Chubby FIRE" sits between normal FIRE and Fat FIRE, roughly $60-100k of annual spending ($1.5-2.5M invested). Use the same calculator, just enter your target budget.
Should I hit Coast FIRE first?
It's a great milestone on the way. Once your Coast FIRE number for a fat budget is banked, compounding does the heavy lifting and you can take career risks (like starting a business) that often accelerate Fat FIRE.
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Sources and further reading
The figures and rules on this page rest on the sources below, so you can check them rather than take our word for it.
- Bengen, W. P., Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning, 1994 (FPA reprint, March 2004, member access), the origin of the 4% rule
- Cooley, Hubbard and Walz, Portfolio Success Rates: Where to Draw the Line, Journal of Financial Planning, 2011, the update
- How our calculators work, the formulas, defaults and tax year 2026 constants behind every figure on this site