FIRE Number = annual spending × 25 (the 4% safe withdrawal rule). €40,000/year spending → €1,000,000 invested portfolio = financial independence.
The 4% rule comes from the Trinity Study (1998) refining Bengen 1994: a 60/40 stock/bond portfolio sustained 4% inflation-adjusted withdrawals for 30 years across historical market conditions with high success rate. Modern variants use 3.5% for early retirees (longer horizon) or 4.5% for shorter.
| Year | Net Worth | Deposits | Interest |
|---|---|---|---|
| 1 | $78,400 | $74,000 | $4,400 |
| 2 | $108,852 | $98,000 | $10,852 |
| 3 | $141,506 | $122,000 | $19,506 |
| 4 | $176,521 | $146,000 | $30,521 |
| 5 | $214,067 | $170,000 | $44,067 |
| 6 | $254,327 | $194,000 | $60,327 |
| 7 | $297,498 | $218,000 | $79,498 |
| 8 | $343,789 | $242,000 | $101,789 |
| 9 | $393,427 | $266,000 | $127,427 |
| 10 | $446,653 | $290,000 | $156,653 |
| 11 | $503,726 | $314,000 | $189,726 |
| 12 | $564,926 | $338,000 | $226,926 |
| 13 | $630,550 | $362,000 | $268,550 |
| 14 | $700,917 | $386,000 | $314,917 |
| 15 | $776,372 | $410,000 | $366,372 |
| 16 | $857,281 | $434,000 | $423,281 |
| 17 | $944,039 | $458,000 | $486,039 |
| 18 | $1.04M | $482,000 | $555,069 |
Educational tool. Not financial advice. The 4% rule (Bengen 1994 / Trinity Study 1998) was calibrated on US data 1926–1995; sequence-of-returns risk and inflation regime changes can alter the safe withdrawal rate.
FIRE numbers at the 4% rule
| Annual spending | FIRE number | Tier / context |
|---|---|---|
| €20,000/yr | €500,000 | Lean FIRE (low-cost lifestyle) |
| €30,000/yr | €750,000 | Modest FIRE |
| €40,000/yr | €1,000,000 | Standard FIRE (1M target) |
| €50,000/yr | €1,250,000 | Mid-range FIRE |
| €60,000/yr | €1,500,000 | Comfortable FIRE |
| €80,000/yr | €2,000,000 | Fat FIRE entry-level |
| €100,000/yr | €2,500,000 | Fat FIRE |
| €120,000/yr | €3,000,000 | Fat FIRE comfortable |
| €150,000/yr | €3,750,000 | High-cost-of-living Fat FIRE |
| €200,000/yr | €5,000,000 | Chubby FIRE / VHCOL |
| At 3.5% SWR | × 28.6 spending | More conservative (Bengen 1994 floor) |
| At 4.5% SWR | × 22.2 spending | Slightly more aggressive |
History & origin
The FIRE concept (Financial Independence, Retire Early) was popularised by Vicki Robin and Joe Dominguez in Your Money or Your Life (1992). The 4% safe withdrawal rate originates from William Bengen's 1994 study in the Journal of Financial Planning, refined by the Trinity Study (Cooley, Hubbard, Walz; 1998). Mr. Money Mustache's blog (started 2011) brought the movement to internet mainstream. FIRE math: target = annual spending ÷ SWR (4% → 25× annual spending).
FIRE Calculator — FI Number, Coast FIRE, Lean/Fat FIRE & 4% Rule
Enter your current savings, monthly savings rate, expected returns, and annual expenses to see when you reach financial independence. The chart shows your net worth growing until it crosses the FIRE number.
How to project your FIRE date
- Enter your current invested net worth (assets you'd actually draw from in retirement).
- Set the monthly amount you save and invest, plus your expected annual real return (after inflation).
- Input your target annual expenses in retirement; the calculator multiplies them by 1/withdrawal-rate to get your FIRE number.
- Adjust the withdrawal rate (default 4%) to model lean-FIRE, fat-FIRE or coast-FIRE variants and read the year-by-year trajectory.
Common use cases
- Checking whether your current savings rate gets you to FIRE before age 60.
- Stress-testing the 4% rule against a 3% rate to see how much extra capital that requires.
- Modelling coast-FIRE: how much you'd need today to stop adding contributions and still hit the target by 65.
- Comparing lean-FIRE (€20K/year expenses) against fat-FIRE (€60K/year) on the same income.
About FIRE
FIRE (Financial Independence, Retire Early) means accumulating enough wealth that your investments can cover your annual expenses indefinitely. The standard approach uses the 4% rule: your FIRE number is 25× your annual expenses.
- FIRE number based on withdrawal rate (default 4% rule)
- Net worth growth chart with FIRE line
- Progress bar showing how far you are
- Year-by-year breakdown table
- Adjustable withdrawal rate (2-6%)
- Export chart as PNG or data as CSV
Free. No signup. Inputs stay in your browser. Ads via AdSense (consent required).
Sources (2)
- Bengen, W. P. (1994). Determining withdrawal rates using historical data. Journal of Financial Planning, 7(4), 171–180.
- Cooley, P. L., Hubbard, C. M., & Walz, D. T. (1998). Retirement savings: choosing a withdrawal rate that is sustainable (Trinity Study). AAII Journal, 10(3), 16–21.
These are the original publications and regulations the formulas in this calculator are based on. Locate them by author and year on Google Scholar, SSRN, or the U.S. Government Publishing Office.
By Marco B. ·