What's my FIRE number?
Guide · By Kevin Lan · Updated September 2026
Your FIRE number is the amount you need invested to live off your portfolio. Here's the formula, an example, and a calculator.
The formula
Your FIRE number is your annual retirement expenses divided by your safe withdrawal rate. At the common 4% rule, that is your yearly spending times 25. If you expect to spend $50,000 a year, your FIRE number is about $1,250,000 ($50,000 ÷ 0.04).
It is the portfolio size that can fund your spending indefinitely, because a sustainable withdrawal rate lets the remaining balance keep growing to cover future years and inflation.
Your FIRE number at different spending levels
Because the number scales directly with spending, it's easy to read off. At a 4% withdrawal rate (25× expenses):
- $40,000/yr → $1,000,000
- $60,000/yr → $1,500,000
- $80,000/yr → $2,000,000
- $100,000/yr → $2,500,000
Using a more cautious 3.5% rate for a long early retirement raises each figure by about 14% (the multiple becomes ~28.6× instead of 25×).
Plan in today's dollars
Enter spending in today's dollars and use a real (after-inflation) return. Since 1928, U.S. stocks have returned roughly 10% a year before inflation and about 7% after it; a portfolio that holds bonds as well has earned less, so 4% to 5% real is a common cautious assumption for a balanced mix. The calculator's default of 7% real reflects a stock-heavy portfolio's history; lower it to plan more conservatively. Planning in real terms keeps your FIRE number meaningful decades out without guessing future price levels.
Your spending figure should include the taxes you'll owe on withdrawals. The 4% rule assumes the withdrawal covers your total outflow, not just take-home spending.
Common mistakes to avoid
- Leaving out taxes. Withdrawals are usually taxable, so a tax-inclusive spending figure keeps the number honest.
- Using a nominal return. A 7% nominal return with 3% inflation is only ~4% real; planning on the nominal figure overstates what your money will buy decades out.
- Forgetting healthcare. In the U.S., insurance before Medicare age (65) is a real line item for early retirees, so build it into your spending.
- Anchoring on 4% for a 45-year retirement. The 4% rule was tested on 30 years; longer horizons often warrant a lower withdrawal rate, which raises your number.
How many years until you reach it
Once you know the number, the question becomes when. That depends on what you have invested now, how much you add each year, and your expected real return. The calculator below solves for the crossover year, and the app turns that date into a live home-screen countdown that moves closer as you invest.
References
- Bengen WP. Determining withdrawal rates using historical data. Journal of Financial Planning. 1994;7(4):171–180. The paper that introduced the 4% withdrawal guideline.
- Cooley PL, Hubbard CM, Walz DT. Retirement savings: choosing a withdrawal rate that is sustainable. AAII Journal. 1998;20(2):16–21. Widely known as the “Trinity study.”
- Damodaran A. Historical annual returns on U.S. stocks, bonds and bills (1928–present). NYU Stern School of Business. pages.stern.nyu.edu/~adamodar
FIRE calculator
It runs in your browser. Nothing is sent anywhere.
No account, no ads, and we never see your numbers.
Frequently asked questions
What is the FIRE number formula?
FIRE number = annual retirement expenses ÷ safe withdrawal rate. At a 4% withdrawal rate that equals your yearly spending × 25.
What's a good FIRE number?
There's no universal figure. It's personal, because it's your own spending ÷ your withdrawal rate. At 4%, a $40,000 budget needs $1,000,000, a $60,000 budget $1,500,000, and a $100,000 budget $2,500,000. Lower spending means a smaller number and an earlier finish.
Is the FIRE number 25 times expenses?
Only at a 4% safe withdrawal rate. At 3.5% it's about 28.6× expenses; at 5% it's 20×. The multiple is 1 divided by your withdrawal rate.
Should my expenses include taxes?
Yes. The 4% rule assumes the withdrawal covers your total spending, including any income tax owed on withdrawals, so enter a tax-inclusive number.
