Fat FIRE means retiring early without sacrificing lifestyle. Calculate the portfolio size you need to support $100K+ in annual spending indefinitely.
Fat FIRE is the opposite of Lean FIRE. Instead of optimizing for the smallest possible nest egg, you build a portfolio large enough to support a comfortable upper-middle-class lifestyle indefinitely — typically $100,000 to $250,000+ in annual spending. It usually requires a Fat FIRE number of $2.5M to $7M+, depending on target spending and withdrawal rate.
Fat FIRE Number = Generous Annual Expenses ÷ Safe Withdrawal Rate
If you want to spend $150,000/year in retirement and use a conservative 3.5% withdrawal rate (common in Fat FIRE because of longer retirement horizons), your Fat FIRE number is $4,285,714. At a standard 4%, it would be $3,750,000.
Lean FIRE: Under $40K/year retirement budget. Number around $1M.
Regular FIRE: $40K–$100K/year. Number around $1M–$2.5M.
Fat FIRE: $100K+/year, often $150K–$250K+. Number $2.5M–$7M+.
Chubby FIRE: An informal middle tier — comfortable but not luxurious, around $80K–$120K/year.
Most Fat FIRE planners use 3–3.5% rather than the classic 4% because they're typically retiring earlier (longer horizon = more sequence risk) and have more to lose if returns disappoint. A lower withdrawal rate means a larger nest egg target but better long-term safety.
It's challenging without high household income (typically $200K+) or significant equity events like business sales or stock vesting. Most Fat FIRE achievers come from tech, finance, medicine, law, or entrepreneurship. That said, dual-income high-savers in any field can hit it with enough time.
Healthcare costs are baked into your annual expense estimate. Most Fat FIRE planners budget $20,000–$30,000/year for premiums, deductibles, and out-of-pocket costs for a family before Medicare eligibility at 65.
Generally no — primary residence equity isn't easily accessible and doesn't generate income. Most planners exclude home equity from their FIRE number unless they plan to downsize or use a HELOC strategy.
Lifestyle inflation. The same skills that help you earn enough to hit Fat FIRE also tend to expand your baseline expenses. Many Fat FIRE candidates push their target up year after year as their tastes upgrade, which delays the actual retirement indefinitely.