Enter your expenses, savings and return. See your FIRE number and inflation-adjusted timeline.
What is my FIRE number? Multiply your expected annual retirement spending by 25. That ratio comes from the 4% safe withdrawal rate — the rate at which a 60/40 stock-bond portfolio survived every 30-year retirement period in U.S. history (Trinity Study, 1998). $50,000/year of spending → $1.25M FIRE number. $80,000/year → $2M. $120,000/year → $3M.
The calculator below adjusts for inflation during accumulation (most don’t) and lets you flex the withdrawal rate — use 3.5% for a longer or earlier retirement, 4.5%–5% if you have Social Security or part-time income to cushion the early years.
| Annual spending | 4% (25×) | 3.5% (28.5×) | 3% (33×) |
|---|---|---|---|
| $40,000 (Lean FIRE) | $1,000,000 | $1,140,000 | $1,320,000 |
| $60,000 | $1,500,000 | $1,710,000 | $1,980,000 |
| $80,000 (Regular FIRE) | $2,000,000 | $2,280,000 | $2,640,000 |
| $120,000 (Fat FIRE) | $3,000,000 | $3,420,000 | $3,960,000 |
| $200,000 (Chubby/Fat FIRE) | $5,000,000 | $5,700,000 | $6,600,000 |
Lower withdrawal rates — 3% to 3.5% — are appropriate when retiring early (40-year+ horizon), in a richly-valued market, or without Social Security to backstop late life.
Methodology: FIRE number = Annual Expenses ÷ Safe Withdrawal Rate. Calculator inflates expected expenses to your retirement year (most calculators skip this and understate timeline by 3–5 years). Investment growth uses standard compound math with monthly contributions.
The FIRE Number Calculator tells you exactly how much money you need saved and invested before you can stop working permanently. It's designed for anyone pursuing Financial Independence, Retire Early — whether your target is 35, 45, or 55. Enter your expected annual expenses and the calculator shows the portfolio size that can sustain you indefinitely.
Your FIRE number is calculated using the 4% rule, derived from the Trinity Study — a landmark 1998 analysis of historical stock and bond returns. The formula is simple: Annual Expenses ÷ 0.04 = FIRE Number. If you spend $50,000 per year, you need $1,250,000 invested. The 4% represents the safe withdrawal rate — the percentage of your portfolio you can withdraw annually without running out of money over a 30-year period.
Knowing your FIRE number transforms retirement planning from vague aspiration into a concrete target. Once you know the number, every dollar saved becomes measurable progress toward that finish line. Studies show that people with a specific financial goal save 2–3x more aggressively than those without one — because the number makes the goal feel real and achievable.