FIRE Number Calculator
Calculate your exact FIRE number — the total portfolio needed to retire on investment income alone. Adjust your withdrawal rate and see the monthly savings required to get there.
To get started, enter the following information:
Annual expenses
Enter what you spend per year in retirement — or switch to monthly mode and enter your monthly budget. This is the single most important input: your FIRE number scales directly with your expenses. Lower spending means a smaller target.
Monthly or annual toggle
Use the toggle above the input to switch between entering a monthly figure or an annual total. The calculator multiplies monthly values by 12 automatically.
Withdrawal rate
The default is 4% — the widely-cited safe withdrawal rate from the Trinity Study. Drag the slider to model more conservative (3–3.5%) or more aggressive (4.5–5%) rates. Lower rates mean a larger, safer portfolio target.
Read your results
The calculator instantly shows your FIRE number, annual withdrawal, monthly withdrawal, and a savings table with monthly contribution targets for 10–30 year timelines. Adjust any input to see changes in real time.
FIRE Number
The total investment portfolio you need to retire. Once you hit this number, investment returns alone can fund your lifestyle indefinitely — you never need to work again unless you choose to.
Annual Withdrawal
How much of your portfolio you spend each year in retirement. This equals your annual expenses. As long as your portfolio grows faster than you withdraw, it should last forever.
Monthly Withdrawal
Your annual withdrawal split into monthly spending. Use this to compare directly to your current monthly budget and visualize what retirement cash flow looks like.
Savings Table
The monthly savings required to reach your FIRE number in 10–30 years, assuming a 7% annual return. Shorter timelines require dramatically higher monthly contributions.
The FIRE number formula is elegantly simple. Divide your annual retirement expenses by your safe withdrawal rate, and you get the exact portfolio needed to sustain your lifestyle indefinitely.
FIRE Number = Annual Expenses ÷ Withdrawal Rate
Example: $40,000 ÷ 0.04 = $1,000,000
The savings table uses the future value of an annuity formula to find how much you need to save monthly to hit your target by a given date:
PMT = FV × r / ((1 + r)ⁿ − 1)
FV = FIRE number · r = monthly rate · n = total months
The 4% Rule origin
William Bengen's 1994 Trinity Study found that a diversified portfolio historically survived a 4% annual withdrawal rate for 30+ years. At 4%, your FIRE number is 25× your annual expenses.
Why lower rates are safer
A 3% withdrawal rate means a 33× FIRE number — 33% more to save, but your money is far less likely to run out. Early retirees planning 50+ year retirements often target 3–3.5%.
Annual vs. monthly input
Use the toggle to enter expenses as a monthly budget instead of an annual figure. The calculator automatically multiplies by 12 before applying the formula.
The savings table assumes 7%
The monthly savings needed chart uses 7% annual return (nominal) as the growth assumption — a commonly cited long-run US stock market average. Your actual results will vary.
The Minimalist — $30K/year lifestyle
The Standard Retiree — $50K/year
The Conservative Early Retiree — 3.5%
The minimalist lifestyle at $30k/year requires only $750,000 — achievable much sooner than the standard path. The conservative early retiree drops to 3.5% withdrawal for a safer 50-year horizon, but pays a $464,000 premium on the FIRE number compared to $50k at 4%. Use the withdrawal rate slider to explore how much safety costs.
The 4% rule is based on historical analysis of US market data. William Bengen studied rolling 30-year periods from 1926 onward and found that a portfolio of 50–75% stocks could sustain a 4% annual withdrawal without running out of money in any historical period.
The rule became mainstream after the Trinity Study (1998) by Cooley, Hubbard, and Walz extended Bengen's work with different portfolio compositions and time horizons.
For early retirees, a 40–50 year retirement horizon is common. More recent research — including updated Trinity Study data — suggests the 4% rule holds for most historical periods at 30 years, but retirees should consider 3–3.5% for very long retirements.
33× annual expenses
Very conservative — longest runway, minimal risk
28.6× annual expenses
Conservative — recommended for 40–50 year retirements
25× annual expenses
Standard — the Trinity Study benchmark
22.2× annual expenses
Moderate — works well with some flexibility
20× annual expenses
Aggressive — requires strong returns or spending flexibility
Your FIRE number is the total investment portfolio you need to retire permanently. Once you reach it, your portfolio generates enough returns to cover all expenses indefinitely. At a 4% withdrawal rate, your FIRE number is exactly 25× your annual spending.
FIRE Number = Annual Expenses ÷ Withdrawal Rate. For $40,000 in annual expenses at a 4% withdrawal rate: $40,000 ÷ 0.04 = $1,000,000. This is the amount that, invested in a diversified portfolio, should sustain $40,000 in annual withdrawals indefinitely.
The 4% rule works well for 30-year retirements. For early retirement spanning 40–50 years, many FIRE practitioners use 3–3.5% to reduce the risk of running out of money. The more conservative your withdrawal rate, the larger your FIRE number — but the safer your retirement.
Yes, indirectly. Your expenses are stated in today's dollars, and the safe withdrawal rate research accounts for inflation-adjusted withdrawals. As long as your portfolio is invested in assets that historically beat inflation (like broad market index funds), the real value of your portfolio is maintained.
If you plan to receive Social Security, you can subtract that annual income from your expenses before calculating your FIRE number. Example: $50,000 expenses − $15,000 Social Security = $35,000 from portfolio. Your FIRE number would then be $35,000 ÷ 0.04 = $875,000 — significantly lower.
The savings table assumes a 7% nominal annual return — a commonly cited long-run average for a diversified US stock market portfolio. This is before inflation. Real (inflation-adjusted) returns would be lower, around 4–5%.
Yes. This calculator focuses on two things: your target number, and how much you need to save to reach it. The full FIRE Calculator adds your current portfolio, income, contributions, and inflation to project when you'll actually reach FIRE and at what age.
This calculator does not model taxes. Depending on your account types (taxable, traditional IRA/401k, Roth), your effective tax rate in retirement varies significantly. Roth accounts are generally tax-free in retirement; traditional accounts are taxed as ordinary income. Consult a financial advisor for a tax-aware model.
Get your full FIRE projection
Add your current portfolio, income, and contributions to see exactly when you'll reach FIRE and at what age.
Find your Coast FIRE number
Calculate the lump sum you need invested today so compound growth alone carries you to your FIRE number — no more contributions needed.
Calculate your savings rate
See how your current savings rate maps to years until financial independence — and how much faster you get there by saving more.
Model safe withdrawal scenarios
Use the 4% Rule Calculator to stress-test different withdrawal rates and see how long your portfolio lasts.
FIRE Calculator
Full FIRE projection with your income, expenses, portfolio, and timeline to retirement.
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4% Rule Calculator
Calculate safe annual withdrawals from a portfolio and how long the money lasts.
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Savings Rate Calculator
See how your savings rate maps directly to years until financial independence.
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Coast FIRE Calculator
Find the lump sum needed today so compound growth alone reaches your FIRE number.
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Compound Interest Calculator
Project how investments grow over time with regular contributions.
Articles on FIRE number strategy, the Trinity Study, safe withdrawal rates, and early retirement planning are coming soon. Check back or explore the full FIRE Calculator in the meantime.
Disclaimer: This calculator is for educational and informational purposes only. It does not constitute financial, investment, or tax advice. All projections are estimates based on hypothetical scenarios — actual returns vary and past performance does not guarantee future results. The 4% rule and safe withdrawal rate research is based on historical US market data and may not reflect future market conditions. Consult a qualified financial advisor before making investment decisions.