— Retirement & FIRE
Fat FIRE Calculator
Calculate the FIRE number for a generous retirement budget. Enter target spending, savings, return, and withdrawal rate to see the fat FIRE corpus, years to reach it, progress, and how taxes, legacy goals, or cautious withdrawal assumptions change the target.
Years to fat FIRE
26 yrs 3 mos
- Fat FIRE number
- $3,000,000
- Progress to fat FIRE
- 6.67%
- Fat FIRE age
- 62
- Regular FIRE number
- $1,800,000
- Lean FIRE number
- $1,200,000
- At a cautious 3% rate
- $4,000,000
- Fat number (nominal at FIRE)
- $5,737,988.85
Try: Fat FIRE on $120k a year, Cautious 3.5% rate, By savings rate (40% of $250k), With a $1M legacy goal
— Accumulation to the fat-FIRE number
| Age | Savings | Growth | Corpus | Fat number |
|---|---|---|---|---|
| 35 | $0 | $0 | $200,000 | $3,000,000 |
| 36 | $50,000 | $8,780 | $258,780 | $3,000,000 |
| 37 | $50,000 | $11,361 | $320,142 | $3,000,000 |
| 38 | $50,000 | $14,055 | $384,197 | $3,000,000 |
| 39 | $50,000 | $16,867 | $451,064 | $3,000,000 |
| 40 | $50,000 | $19,803 | $520,867 | $3,000,000 |
| 41 | $50,000 | $22,867 | $593,734 | $3,000,000 |
| 42 | $50,000 | $26,066 | $669,800 | $3,000,000 |
| 43 | $50,000 | $29,406 | $749,206 | $3,000,000 |
| 44 | $50,000 | $32,892 | $832,098 | $3,000,000 |
| 45 | $50,000 | $36,531 | $918,629 | $3,000,000 |
| 46 | $50,000 | $40,330 | $1,008,959 | $3,000,000 |
| 47 | $50,000 | $44,296 | $1,103,255 | $3,000,000 |
| 48 | $50,000 | $48,436 | $1,201,691 | $3,000,000 |
| 49 | $50,000 | $52,757 | $1,304,448 | $3,000,000 |
| 50 | $50,000 | $57,268 | $1,411,716 | $3,000,000 |
| 51 | $50,000 | $61,978 | $1,523,694 | $3,000,000 |
| 52 | $50,000 | $66,894 | $1,640,588 | $3,000,000 |
| 53 | $50,000 | $72,026 | $1,762,614 | $3,000,000 |
| 54 | $50,000 | $77,383 | $1,889,997 | $3,000,000 |
| 55 | $50,000 | $82,975 | $2,022,972 | $3,000,000 |
| 56 | $50,000 | $88,813 | $2,161,786 | $3,000,000 |
| 57 | $50,000 | $94,908 | $2,306,693 | $3,000,000 |
| 58 | $50,000 | $101,269 | $2,457,963 | $3,000,000 |
| 59 | $50,000 | $107,911 | $2,615,873 | $3,000,000 |
| 60 | $50,000 | $114,843 | $2,780,716 | $3,000,000 |
| 61 | $50,000 | $122,080 | $2,952,797 | $3,000,000 |
| 62 | $50,000 | $129,635 | $3,132,432 | $3,000,000 |
— Crossover to the fat-FIRE number
Download— How it works
Fat FIRE number = generous annual expenses ÷ safe withdrawal rate (×25 at 4%, ×28.5–33 at 3.5–3%), plus any legacy. Other income reduces the expenses first and tax grosses them up; your savings then grow at the real return until the corpus reaches the number.
A bigger number, a longer climb
Fat FIRE is the same arithmetic as any FIRE plan — expenses ÷ a safe withdrawal rate — applied to a generous lifestyle. Because the target scales with spending, a comfortable budget means a large number: at 4%, $120,000 of expenses needs $3 million, against $750,000 for a $30,000 lean budget. Reaching it usually takes a high income, a high savings rate, or a long runway. The calculator shows the years, your fat-FIRE age and progress, with the regular and lean numbers alongside so you can see the whole ladder.
Worked example — age 35, $120,000 expenses, $200k saved, $50,000/year invested, 7% return: Fat FIRE number = $120,000 × 25 = $3,000,000; reached in about 26 years. At a cautious 3% it rises to $4,000,000; regular FIRE (≈ $72k spending) is $1.8M and lean (≈ $48k) is $1.2M.
Why fat FIRE leans conservative
A large, long-horizon, high-spend plan has more to lose, so fat-FIRE planners often use a lower withdrawal rate — 3 to 3.5% rather than 4% — which raises the target (to roughly 28.5–33× expenses) but buys a wider safety margin against bad markets. Tax matters more too: drawing a six-figure income can land in higher brackets, so the calculator grosses up the number for the rate you enter. A legacy or estate goal adds directly on top, since a balance you intend to leave is capital you can’t spend down.
Levers and limits
Other income — a pension, rental, dividends or a business — reduces the spending your portfolio must cover, and so cuts the number; part-time or passion income does the same. A windfall such as an equity event or business sale, common on the fat-FIRE path, shortens the climb when invested. As always the projection assumes a steady real return and ignores sequence-of-returns risk; with a large balance and a long retirement the cautious rate is your buffer. For frugal or middle-of-the-road targets, see the Lean FIRE and Financial Independence calculators.
— Reader questions
What is the fat FIRE number?
Your generous annual expenses divided by your safe withdrawal rate — 25× at 4%. So $120,000 of comfortable spending gives a $3,000,000 fat FIRE number, rising to $4,000,000 at a cautious 3%.
How is fat FIRE different from regular and lean FIRE?
Only the spending assumption changes. Fat FIRE funds a comfortable budget, regular FIRE a typical one (around 60% of fat), and lean FIRE a frugal one (around 40%). The calculator shows all three numbers together.
Why use a 3–3.5% withdrawal rate for fat FIRE?
A large balance and a potentially long retirement leave more exposed to a bad sequence of returns. A lower rate raises the target but adds a safety margin — the calculator shows the bigger figure a cautious 3% implies.
Does a legacy goal change the number?
Yes — it adds directly. A balance you want to leave to heirs or charity is capital you won’t spend, so a $1,000,000 legacy raises the fat FIRE number by $1,000,000 on top of the spending corpus.
Why does tax matter more at fat FIRE?
Drawing a high income can fall into higher tax brackets, so you must withdraw more than you spend to net your target. Enter a tax rate and the calculator grosses up the required corpus accordingly.