FIRE
What Is a FIRE Number?
The 25x rule
The most common way to calculate a FIRE number is to multiply your annual expenses by 25. That multiple comes from a 4% safe withdrawal rate: withdrawing 4% of a portfolio each year, adjusted for inflation, has historically lasted through long retirements without running out. Since 25 is the inverse of 4%, saving 25 times your yearly spending means a 4% withdrawal rate covers it every year. The 4% figure traces back to research on historical US market returns across rolling 30-year periods, which found that a portfolio split between stocks and bonds could sustain that withdrawal rate in the vast majority of historical scenarios, including some of the worst market conditions on record.
The 25x rule is popular because it's simple, not because it's precise. It assumes a reasonably diversified portfolio, a long but not unlimited retirement horizon, and spending that stays roughly level in real terms. Some people use a more conservative 30x or 33x multiple, equivalent to a 3% or 3.3% withdrawal rate, if they're retiring unusually early or want extra of a cushion against a prolonged downturn right after they stop working.
How to calculate your FIRE number
Calculating your own FIRE number starts with knowing your annual expenses, not your income. Add up everything you actually spend in a year: housing, food, insurance, transportation, subscriptions, travel, and everything else, including costs that might change in retirement like healthcare. Multiply that total by 25, and you have your FIRE number under the standard 4% rule. Lower your annual expenses and the number drops with it; spend more and it rises. The formula always scales with your own cost of living, not someone else's, which is why two people with very different incomes can end up with surprisingly similar FIRE numbers if they spend similarly.
Quick reference: FIRE numbers by spending level
| Annual Expenses | FIRE Number (25x) | Monthly Passive Income at 4% |
|---|---|---|
| $30,000 | $750,000 | $2,500 |
| $40,000 | $1,000,000 | $3,333 |
| $50,000 | $1,250,000 | $4,167 |
| $60,000 | $1,500,000 | $5,000 |
| $80,000 | $2,000,000 | $6,667 |
| $100,000 | $2,500,000 | $8,333 |
Want a personalized calculation? Use the FIRE Calculator to factor in your specific expenses, income, and savings rate.
Your number depends on your FIRE type
The 25x rule gives you a baseline, but your actual target shifts with which type of FIRE you're aiming for. For what each type means day-to-day, see What Is FIRE?; here's how each one changes the number itself.
Lean FIRE: often under $1,000,000
Fat FIRE: frequently $2,500,000 or more
Coast FIRE: smaller than your full FIRE number; compound growth covers the rest
Barista FIRE: smaller than your full FIRE number; part-time income covers the gap
Why your FIRE number will move
A FIRE number isn't something you calculate once and forget. It moves as your annual expenses change, whether that's from a move to a cheaper city, a new mortgage, kids, or inflation eroding the value of a fixed target over time. Most people in the FIRE community recalculate their number every year or two using their actual trailing spending, rather than a guess, so the target stays anchored to how they actually live rather than how they expected to live when they first set the goal.
Find your own number
Want to see your FIRE number based on your real income, spending, and savings rate, along with how many years away you are at your current pace? Try the FIRE Calculator, or read What Is FIRE? for the bigger picture behind the number.