The calculator
$60,000 a year at a 4.0% withdrawal rate needs $1,500,000. Saving $30,000 a year on top of $150,000 at 5.0% real gets there in 21.1 years, around age 57. Retiring at 50 instead takes about $55,062 a year.
How to calculate your FIRE number
Your FIRE number is the portfolio that can pay your annual spending for the rest of your life. Divide annual spending by the withdrawal rate you trust. At 4% that is 25 times spending, so $60,000 a year needs $1,500,000. At 3.5% the multiple is about 28.6, and at 3.25% it is about 30.8. Spending is the input that matters most: every $1,000 a year you do not need takes $25,000 to $31,000 off the target.
| Annual spending | At 4.0% | At 3.5% | At 3.25% |
|---|---|---|---|
| $40,000 | $1,000,000 | $1,142,857 | $1,230,769 |
| $50,000 | $1,250,000 | $1,428,571 | $1,538,462 |
| $60,000 | $1,500,000 | $1,714,286 | $1,846,154 |
| $80,000 | $2,000,000 | $2,285,714 | $2,461,538 |
| $100,000 | $2,500,000 | $2,857,143 | $3,076,923 |
| $150,000 | $3,750,000 | $4,285,714 | $4,615,385 |
The rule of 25 calculator is the same division written as a multiple, and the 4% rule calculator turns a portfolio back into a first-year income.
Savings rate vs years to FIRE
Starting from nothing, the time to financial independence depends on one number: the share of take-home pay you save. Income cancels out, because whatever you do not save is what the portfolio will have to replace. At the return and withdrawal rate in the calculator above:
| Savings rate | Years to FIRE |
|---|---|
| 10% | 51.4 |
| 20% | 36.7 |
| 30% | 28.0 |
| 40% | 21.6 |
| 50% | 16.6 |
| 60% | 12.4 |
| 70% | 8.8 |
| 80% | 5.6 |
With the defaults (5% real, 4%), this reproduces the table Mr. Money Mustache made famous in 2012: a 10% savings rate takes about 51 years, 50% about 17, and 70% under 9. Your own rate, with what you have already invested, is the savings-rate figure in the calculator. The savings rate calculator works it out from a salary.
Which withdrawal rate for early retirement?
The 4% rule came from 30-year retirements. Retiring at 40 can mean 50 years of withdrawals, and a longer horizon needs a lower rate or a willingness to cut spending in bad years. In our withdrawal rates by retirement age study (5% mean, 15% volatility, 2% inflation), a rigid 4% lasted in 56% of 30-year retirements and 24% of 50-year ones, while a flexible Guyton-Klinger 4% stayed at or above 99%. That is why many early retirees plan at 3.25% to 3.5%, or keep 4% and pair it with guardrails such as the Guyton-Klinger calculator or the Vanguard dynamic spending calculator.
Types of FIRE
| Type | What changes | Calculator |
|---|---|---|
| Lean FIRE | A frugal budget, often around $40,000 a year or less | Lean FIRE calculator |
| Fat FIRE | A comfortable budget, usually $100,000 a year and up | Fat FIRE calculator |
| Coast FIRE | Stop saving once compounding alone reaches the number by a later age | Coast FIRE calculator |
| Barista FIRE | Part-time income covers part of spending, so the number is smaller | Barista FIRE calculator |
All of them are the same division with a different spending figure or a different stopping rule. The FIRE guide covers how to choose between them.
Assumptions
Contributions at year end, one constant real return, no fees and no taxes. Social Security and pensions are left out, which is conservative for an early retiree: they start decades later and shrink the portfolio you need from then on. The savings rate here is saving divided by saving plus spending, the share of take-home pay you keep. To see how often a plan survives real market sequences, run it through the Monte Carlo retirement calculator.
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