What is Fat FIRE?
Fat FIRE means reaching financial independence with a comfortable budget, commonly $100,000 a year or more. The arithmetic is the same as Lean FIRE with a bigger spending figure: $150,000 a year is $3,750,000 at 4%. The larger portfolio takes more years of saving and leaves more room to absorb a bad decade.
The calculator
$150,000 a year at 4.0% is $3,750,000. From $200,000 plus $20,000 a year at 5.0% real, that is 39.6 years.
How it works
Fat FIRE at this page's $150,000 default is a $3,750,000 nest egg at 4%. The same $200,000 plus $20,000 a year path is decades longer than Lean. Chubby FIRE, the in-between search, is roughly $70,000 to $100,000 a year: still this identity, not a third URL.
Same identity as every other FIRE number: spending divided by the withdrawal rate. The years figure inverts the ordinary-annuity future value. The Lean FIRE calculator is the other end of the same scale. Coast and Barista are the milestones on the way: Coast FIRE calculator, Barista FIRE calculator. The generic identity is the FIRE calculator.
Fat FIRE number by spending
| Annual spending | At 4% | At 3.5% | At 3.25% | At 3% |
|---|---|---|---|---|
| $100,000 | $2,500,000 | $2,857,143 | $3,076,923 | $3,333,333 |
| $125,000 | $3,125,000 | $3,571,429 | $3,846,154 | $4,166,667 |
| $150,000 | $3,750,000 | $4,285,714 | $4,615,385 | $5,000,000 |
| $200,000 | $5,000,000 | $5,714,286 | $6,153,846 | $6,666,667 |
| $250,000 | $6,250,000 | $7,142,857 | $7,692,308 | $8,333,333 |
The 4% rule was built on 30-year retirements. Retiring in your 30s or 40s can mean 50 years of withdrawals, which is why many early retirees plan at 3.25% to 3.5%, a number roughly 29 to 31 times spending, and some use 3%, which is 33 times spending. At 3%, $100,000 a year needs $3,333,333 instead of $2,500,000 at 4%.
Retiring that early also means reaching 401(k) and IRA money before 59½, when withdrawals usually carry a 10% penalty. The 72(t) SEPP calculator sizes penalty-free substantially equal periodic payments, and the Roth conversion ladder calculator plans conversions you can spend five years later.
Lean vs Chubby vs Fat FIRE
The labels describe how much you spend, not a different formula. None of the cutoffs is official; these are the rough bands people usually mean when they use each name.
| Tier | Annual spending | FIRE number at 4% | At 3.5% |
|---|---|---|---|
| Lean FIRE | Up to $40,000 | Up to $1,000,000 | Up to $1,142,857 |
| Regular FIRE | $40,000 to $70,000 | $1,000,000 to $1,750,000 | $1,142,857 to $2,000,000 |
| Chubby FIRE | $70,000 to $100,000 | $1,750,000 to $2,500,000 | $2,000,000 to $2,857,143 |
| Fat FIRE | $100,000 and up | $2,500,000 and up | $2,857,143 and up |
Chubby FIRE is the middle ground: a budget with room for travel or a bigger home, without the full Fat FIRE number. There is no separate Chubby FIRE calculator because the math does not change. Enter $70,000 to $100,000 as your spending on this page: $80,000 a year needs $2,000,000 at 4%. If part of that spending will come from part-time work, the Barista FIRE calculator sizes only the gap.
Fat FIRE and taxes: gross up your spending
The FIRE number has to fund your spending after tax, and at Fat FIRE budgets the tax is large enough to change the answer. Money from a traditional 401(k) or IRA is taxed as ordinary income, so $150,000 to spend means withdrawing about $169,667. Gross up your spending first, then divide by the withdrawal rate:
| After-tax spending | Withdrawal needed | Federal tax | FIRE number at 4% on the withdrawal |
|---|---|---|---|
| $100,000 | $108,682 | $8,682 (8.0%) | $2,717,050 |
| $150,000 | $169,667 | $19,667 (11.6%) | $4,241,675 |
| $200,000 | $233,769 | $33,769 (14.4%) | $5,844,225 |
| $250,000 | $299,300 | $49,300 (16.5%) | $7,482,500 |
That is the worst case. Roth withdrawals are tax-free, and a taxable brokerage account is partly a return of what you put in, with long-term gains taxed at 0% or 15% for most households, so a mix of account types needs a smaller gross-up. State income tax goes on top. This is why tax planning matters more at Fat FIRE than at Lean: the order you draw accounts in and Roth conversions in low-income years can save tens of thousands a year. The retirement tax calculator estimates the tax on your own mix, and the withdrawal order calculator compares drawing taxable, tax-deferred and Roth money in different orders.
The income and years of work Fat FIRE takes
A $3,750,000 target is mostly a savings problem. Starting from $200,000 invested at a 5% real return, this is what you would need to save each year to get there:
| Years to Fat FIRE | Saving each year | Monthly |
|---|---|---|
| 10 years | $272,241 | $22,687 |
| 15 years | $154,515 | $12,876 |
| 20 years | $97,361 | $8,113 |
| 25 years | $64,381 | $5,365 |
Add what you spend while working, plus tax on your pay, to see the income behind each row. Saving about $97,361 a year for 20 years while living on $150,000 points to a household income of roughly $300,000 or more before tax. That is why Fat FIRE is mostly reached by high earners, business owners, or people who sell a company or receive equity, and why many who aim for it take longer than they first planned.
Healthcare and inflation at Fat FIRE
Healthcare. Before Medicare at 65 you buy your own cover. The ACA premium tax credit depends on modified adjusted gross income, which counts taxable withdrawals but not Roth money or the cost basis you sell from a brokerage account. Large taxable withdrawals usually put a Fat FIRE household above the subsidy limit and onto full-price premiums, which for a couple in their 50s can run well into five figures a year. The ACA subsidy cliff calculator shows where the credit stops, and the health insurance before Medicare guide compares the options.
Inflation. This calculator works in today's dollars with a real return, so ordinary inflation is already in the math. The risk is lifestyle inflation and a budget weighted toward costs that have often risen faster than prices overall, such as healthcare, college and services. If your spending grows faster than inflation after you retire, the withdrawal rate creeps up each year, so leave room in the number or use a lower rate.
Is Fat FIRE realistic, and is it worth it?
It is realistic for high savers, and it costs years. From $200,000 invested, saving $50,000 a year at a 5% real return reaches a $1,500,000 Regular FIRE number in 15.0 years and a $3,750,000 Fat FIRE number in 28.2 years. Saving $100,000 a year cuts the Fat FIRE wait to 19.7 years.
What those extra years buy is a margin. A Fat FIRE budget usually includes spending you can cut in a bad market, such as travel, so the plan can absorb a crash by trimming luxuries rather than essentials. Many people stop short of the full number: Chubby FIRE, or Barista FIRE with some work income, gets most of the freedom for a lot less saving.
Assumptions
Contributions at year end, one real return, no fees, no taxes. The default spending figure is a reference point, not a recommendation.