FIRE Number Calculator

Calculate your Financial Independence, Retire Early (FIRE) target. Enter annual expenses and withdrawal rate to find your number, with timeline to reach it.

A FIRE number calculator determines the investment portfolio size needed to retire early and live off investment returns indefinitely, based on the Financial Independence, Retire Early (FIRE) movement's core principle: save 25× your annual expenses and withdraw 4% per year — the safe withdrawal rate derived from historical market data — without running out of money. The "4% rule" originates from the 1994 Trinity Study, which found that a portfolio of 50–75% equities sustained 30 years of withdrawals in 95%+ of historical scenarios. Loan Payment Calculator and Mortgage Calculator are essential for planning the accumulation phase to reach your FIRE number.

FIRE has several variants: Lean FIRE (minimal lifestyle, lower expenses); Fat FIRE (comfortable lifestyle, larger number); Barista FIRE (part-time work to supplement a smaller portfolio); and Coast FIRE (stop contributing and let existing savings compound to a target by traditional retirement age). Understanding which variant aligns with your lifestyle goals determines how ambitious the savings target needs to be.

Enter your expected annual expenses in retirement — be realistic about your lifestyle; many FIRE planners use current expenses minus work-related costs as a starting point.
FIRE number = annual expenses × 25 (4% rule) or × 30 (3.33% rule for longer horizons).
Enter your current investment portfolio value and annual savings rate.
Enter expected annual real (inflation-adjusted) return (5–6% for a global equity portfolio is a common conservative assumption).
The calculator shows years to FIRE, projected date, and sensitivity to different return assumptions.
Subtract any guaranteed income (state pension, defined benefit pension, rental income) from annual expenses before calculating — this significantly reduces the required portfolio.

FIRE number formula

FIRE number = Annual expenses × 25 (4% safe withdrawal rate)

Conservative FIRE number = Annual expenses × 30 (3.33% SWR, for 40+ year horizon)

Adjusted FIRE number = (Annual expenses − Guaranteed income) × 25

Worked example: Annual expenses 30,000. State pension covers 12,000 from age 67. Net expenses portfolio must fund: 18,000. FIRE number = 18,000 × 25 = 450,000. Current savings 80,000, saving 20,000/year at 5% real return → approximately 13 years to reach FIRE number.

Interpreting your FIRE number

Safe withdrawal rate research

The 4% rule (Bengen, 1994; Trinity Study, 1998) was based on US market data 1926–1976 for 30-year retirements. For early retirees with 40–60 year horizons, research suggests 3.5% (× 28.6) or 3.25% (× 30.8) may be more appropriate. Global diversification improves safe withdrawal outcomes vs single-market portfolios. Variable withdrawal strategies — reducing withdrawals during market downturns — significantly improve portfolio survival probability. The 4% rule assumes annual inflation adjustments; abandoning inflation adjustments in bad market years is one of the most effective adaptive strategies.

Finance tips and best practices

Reduce annual expenses to reduce your FIRE number — every 1,000/year reduction in spending reduces the required portfolio by 25,000 at a 4% withdrawal rate.
Factor in guaranteed income sources — state pension, defined benefit pension, or rental income each reduce the required portfolio significantly; always model net of these.
Use a globally diversified equity index fund — home-country-only equity has historically had lower risk-adjusted returns; global diversification reduces sequence-of-returns risk.
Plan for sequence-of-returns risk — a major market crash in years 1–5 of retirement can deplete a portfolio even if long-run returns are adequate; hold 1–2 years of expenses in cash or short-dated bonds.
Consider Barista FIRE — even a modest part-time income dramatically reduces the withdrawal rate required and extends portfolio longevity substantially.

To cover 25,000/year in retirement expenses at a 4% withdrawal rate requires a portfolio of 625,000; at 3.5% SWR (for a 40-year horizon) it requires 714,286.
Increasing savings rate from 20% to 50% of income reduces years to FIRE by approximately 15–20 years, assuming the same return rate.
Every additional year of part-time work in early retirement (earning 10,000–15,000/year) can reduce the required portfolio at retirement by approximately 250,000–375,000 at a 4% SWR.
The earliest realistic FIRE age for most people starting from zero at 25 is approximately 40–45, assuming a 50–60% savings rate and 6% real return (net of fees).

Common mistakes to avoid

Using the 4% rule for a 50-year retirement without adjustment — the original research covered 30-year retirements; longer horizons typically require a 3.25–3.5% withdrawal rate.
Not accounting for inflation in the projection — use real (inflation-adjusted) return rates and increase annual expense figures for inflation in the projection.
Calculating FIRE number without adjusting for guaranteed income — state pensions and defined benefit pensions can substantially reduce the required portfolio.
Failing to plan for healthcare costs in pre-retirement age — before government healthcare schemes kick in, private healthcare costs can be a significant budget item for early retirees.

FIRE planning projections are mathematical illustrations based on assumed investment returns derived from historical data. Past performance does not guarantee future results, and investment returns can be negative in any given period. State pension and defined benefit pension entitlements vary by country and are subject to legislative change. Tax treatment of pension withdrawals, ISA proceeds, and investment income varies by jurisdiction. For personalised FIRE planning, consult a regulated independent financial adviser or certified financial planner authorised in your country. This calculator does not constitute financial advice.