Every half-percent of caution costs real money: the same spending needs $3.5M at 4% but $4.7M at 3% — the glowing dot is your setting. Choosing a withdrawal rate is choosing how many extra working years to trade for sleep quality.
Where the multiplier comes from: the 4% rule traces to the 1998 Trinity study — historical U.S. backtests finding that an initial 4% withdrawal, inflation-adjusted yearly, survived essentially every 30-year period on record. Chubby retirees quietly amend it for two reasons: retiring at 45 means a 45-year horizon, not 30, and a bigger portfolio makes the absolute stakes of failure higher. Hence the community's drift to 3.5% — a 28.6× multiple instead of 25×. The band definitions themselves are internet folk taxonomy, argued in every forum thread; the arithmetic between spending, rate and portfolio is the part that's actually solid.
Chubby FIRE number calculator — annual spending of $100k–$200k converted to a target portfolio at your chosen safe withdrawal rate, with the full lean-to-fat FIRE ladder.
Your portfolio in today's dollars, compounding month by month toward the dashed target line — the glowing dot is arrival day. Notice the curve steepening: in the final years the market contributes more than you do.
Coast chubby, explained: the coast number is what you'd need invested today so that compounding alone — zero further contributions — delivers your chubby number by traditional retirement at 65. Cross it and every dollar you save after that is purely about buying years earlier than 65. It reframes the grind: you're not saving for retirement forever, you're saving until the portfolio can finish the job without you. The mechanics of that takeoff live in our compound interest calculator; what inflation would do to these numbers if we hadn't used real dollars, in the inflation calculator.
Chubby FIRE timeline calculator — years to your target from current savings and monthly investing at a real return, with your FI age, coast-to-65 number and portfolio milestones.
An illustrative chubby budget, scaled to your spending. The amber bar is the one that surprises people: retire at 45 and you're buying your own health insurance for twenty years before Medicare — the boss battle of American early retirement.
The healthcare asterisk on everything: pre-Medicare coverage for a couple routinely runs $15,000–$25,000 a year in premiums and out-of-pocket costs on U.S. marketplace plans — and unlike travel or restaurants, it can't be trimmed in a bad market year. Serious chubby plans treat it as a fixed line with its own inflation rate, and many structure taxable income deliberately around marketplace subsidy cliffs. That, plus Roth conversion ladders and the 0% capital-gains bracket, is why early-retiree tax planning is a genre of its own — worth reading deeply, none of it advice from a web page.
What chubby FIRE spending looks like — an illustrative $100k–$200k retirement budget with housing, travel, food and the pre-Medicare healthcare line that dominates early-retirement planning.
Identical portfolios, identical spending, identical crash — the only difference is when it lands. An early crash forces you to sell depressed assets to eat, and the portfolio never rebuilds its base; a late crash hits money that already finished compounding. This asymmetry has a name — sequence-of-returns risk — and it is the entire reason withdrawal rates are set below what average returns would suggest.
Chubby's built-in airbag: a lean retiree spending $35k has nothing to cut when markets fall; a chubby budget is a third discretionary or more — travel deferred, restaurants downgraded, the kitchen remodel postponed. Cutting spending 20% in a crash year attacks sequence risk at its exact mechanism (selling less while assets are down), which is why flexible-spending rules test so much better than fixed ones, and why the comfortable tier of FIRE is, somewhat unfairly, also the safer one. This lab is a deliberately simplified model — one crash, steady returns otherwise — built to show the mechanism, not to predict your future.
Sequence-of-returns risk demonstrated live — the same market crash in year 1 versus year 15 of a chubby FIRE retirement, withdrawal rates at the trough, and why spending flexibility is the real safety margin.
Typical portfolio bands by tier, in millions — floating bars because these are community conventions with fuzzy edges, not regulations. Chubby is the third rung: past the spreadsheet-austerity of lean, short of the private-chef tier above.
A word from the skeptics' bench, kept on purpose: most FIRE math was stress-tested by people who started investing after 2009, U.S. historical returns are history's best case, healthcare and long-term care can break clean spreadsheets, and "what will you do all day" turns out to be a real question with a divorce-statistics footnote. None of that breaks the arithmetic on this page — spending, rate, portfolio — it just means the arithmetic is the easy part. Related machinery: our compound interest, rent vs buy and inflation calculators, and our standard FIRE calculator for the classic 25\u00D7 math.
The FIRE movement from Your Money or Your Life to r/ChubbyFIRE — lean, regular, chubby, fat, coast and barista tiers, chubby's comfortable-not-luxurious niche, and the critiques worth taking seriously.