FIRE Number by Expenses
Your FIRE number is the amount you need invested to cover your annual expenses from portfolio withdrawals indefinitely. The quickest estimate is the 25x rule: multiply your yearly spending by 25, which is the same as assuming a 4 percent safe withdrawal rate. So $40,000 a year in expenses means a FIRE number of about $1,000,000; $60,000 a year means $1,500,000. A more cautious 3.5 percent withdrawal rate raises those targets by roughly 14 percent. This page shows the full breakdown by expenses and by withdrawal rate.
The short answer
Take your expected annual expenses in retirement and multiply by 25. That is your FIRE number under the 4 percent rule. Spend $40,000 a year and the target is about $1,000,000; spend $50,000 and it is $1,250,000; spend $80,000 and it is $2,000,000. The number is driven entirely by your spending, not your income, which is why lowering expenses lowers the finish line.
Find your own number: the FIRE calculator turns your expenses and savings rate into a target and an estimated timeline to reach it.
FIRE number by annual expenses
Using the 25x rule (a 4 percent withdrawal rate), here is the target for a range of spending levels:
| Annual expenses | Monthly expenses | FIRE number (25×) |
|---|---|---|
| $30,000 | $2,500 | $750,000 |
| $40,000 | $3,333 | $1,000,000 |
| $50,000 | $4,167 | $1,250,000 |
| $60,000 | $5,000 | $1,500,000 |
| $80,000 | $6,667 | $2,000,000 |
| $100,000 | $8,333 | $2,500,000 |
Every $10,000 of annual spending adds $250,000 to the target. That direct link is why cutting recurring costs is so powerful for anyone chasing FIRE — it shrinks the number twice over, by needing less and letting you save more.
By withdrawal rate
The 4 percent rule is the usual starting point, but the rate you choose changes the multiple. A lower, more conservative rate means a larger portfolio. Here is $40,000 of annual expenses across several withdrawal rates:
| Withdrawal rate | Multiple | FIRE number |
|---|---|---|
| 3.0% | 33.3× | $1,333,333 |
| 3.5% | 28.6× | $1,142,857 |
| 4.0% | 25.0× | $1,000,000 |
| 4.5% | 22.2× | $888,889 |
| 5.0% | 20.0× | $800,000 |
Many people planning a long early retirement lean toward 3.5 percent for a bigger safety margin, accepting a larger target in exchange for more confidence the money lasts. See what FIRE is for how the withdrawal rate ties into the whole strategy.
From monthly expenses
If you budget monthly, multiply your monthly spending by 12 to get the annual figure, then by 25. Or just multiply monthly expenses by 300:
| Monthly expenses | Annual expenses | FIRE number (25×) |
|---|---|---|
| $2,000 | $24,000 | $600,000 |
| $3,000 | $36,000 | $900,000 |
| $4,000 | $48,000 | $1,200,000 |
| $5,000 | $60,000 | $1,500,000 |
The shortcut works because 12 months times 25 years equals 300. A $3,000-a-month lifestyle needs about $900,000 invested to sustain it under the 4 percent rule.
Lean, regular, and fat FIRE
The same math produces very different numbers depending on the lifestyle you are funding:
- Lean FIRE — spending under roughly $40,000 a year, so a target under about $1,000,000. It relies on a frugal, low-cost lifestyle.
- Regular FIRE — a typical middle-class budget of $40,000 to $80,000 a year, needing about $1,000,000 to $2,000,000.
- Fat FIRE — a comfortable or high-spending lifestyle of $100,000 a year or more, requiring $2,500,000 and up.
None is more “correct” than another — they simply reflect different spending, and the 25x rule scales cleanly across all of them.
The math behind it
The FIRE number comes straight from your withdrawal rate:
At a 4 percent withdrawal rate, dividing by 0.04 is the same as multiplying by 25 — hence the 25x rule. Choose a 3.5 percent rate and you divide by 0.035, or multiply by about 28.6. The withdrawal rate is really an assumption about how much a diversified portfolio can safely pay out each year without running dry over a long retirement. To see how contributions and compounding get you to the target, try how much $250 a month grows in 30 years.
Assumptions behind these figures
- A fixed withdrawal rate. The tables assume you withdraw a constant percentage (4 percent unless stated) of the starting portfolio, adjusted for inflation.
- Expenses stay roughly constant in real terms. The number reflects today's spending; large lifestyle changes shift the target.
- Taxes and health care are part of expenses. Use total real spending in retirement, not pre-tax income.
- A guideline, not a guarantee. The 4 percent rule is based on historical data; a poor sequence of early returns can still require flexibility.
Frequently asked questions
The bottom line
Your FIRE number is simpler than it sounds: annual expenses times 25, or divided by your chosen withdrawal rate. Spend $40,000 a year and you need about $1,000,000; spend more and the target rises in direct proportion. Because it tracks spending rather than income, the fastest way to move the finish line closer is to know — and manage — your real expenses.
Turn your own numbers into a target and a timeline with the FIRE calculator, and read what is FIRE for the full strategy.
Disclaimer: This page is for general educational purposes only and is not financial advice. The 4 percent rule and 25x rule are historical guidelines, not guarantees; actual safe withdrawal rates vary with markets, inflation, taxes and how long a retirement lasts. Consider speaking with a qualified financial professional before making decisions about your own money.