FIRE Calculator
FIRE (Financial Independence, Retire Early) is a movement built on accumulating enough invested assets to sustain your living expenses indefinitely, enabling retirement much earlier than traditional age 65. Your FIRE number is the portfolio size needed to support your annual expenses using a sustainable withdrawal rate (typically 4 percent annually). This calculator finds your FIRE number, shows your progress toward it, and projects how many years until you reach financial independence based on your current savings, annual contribution rate and expected investment returns. Enter your annual expenses, current invested savings, how much you save annually and your expected return rate. The tool generates a year-by-year projection showing your growing portfolio balance until you reach your FIRE number. The 4% rule is a historical guideline based on decades of market data, but consider consulting a financial advisor for your specific situation, particularly for retirements longer than 30 years.
With $50,000/year in expenses and a 4% safe withdrawal rate, your FIRE number is --. You are currently -- of the way there, and could reach FIRE in approximately -- (target age: --).
The 4% rule is a historical guideline, not a guarantee. Sequence of returns risk, inflation, healthcare costs, and actual spending in retirement all affect outcomes. Consider consulting a fee-only financial advisor.
Year-by-year portfolio projection
Your projected portfolio value each year until FIRE (or 50 years, whichever comes first).
| Year | Age | Portfolio value | FIRE progress |
|---|---|---|---|
| Enter values above to generate the projection. | |||
How the FIRE number is calculated
Your FIRE number is the portfolio size that, when drawn down at your chosen safe withdrawal rate, exactly covers your annual expenses. The formula follows directly from the definition of the withdrawal rate:
FIRE number = annual expenses / (SWR / 100)
e.g. $50,000 / 0.04 = $1,250,000 (at 4% SWR)
Years to FIRE is found by solving for n in the future value equation for a growing annuity:
FV(n) = savings x (1+r)^n + annualContrib x ((1+r)^n - 1) / r
Find smallest n where FV(n) >= FIRE number
Worked example
Age 35, $50,000 expenses, $100,000 current savings, $24,000/year saved, 7% return, 4% SWR:
- FIRE number = $50,000 / 0.04 = $1,250,000
- Current progress = $100,000 / $1,250,000 = 8%
- Solve numerically: portfolio exceeds $1,250,000 at approximately year 20
- Target FIRE age = 35 + 20 = 55
The 4% rule: origins and limitations
William Bengen's 1994 study, widely cited in personal finance, analysed US market returns from 1926 onward and found that a 4% initial withdrawal rate (inflation-adjusted each year) would have lasted at least 33 years in every historical 30-year period tested. The Trinity Study (Cooley, Hubbard and Walz, 1998) examined a range of portfolio allocations and withdrawal rates, reaching broadly consistent conclusions.
The CFPB's retirement planning resources at consumerfinance.gov provide the government context for withdrawal planning, including how Social Security income affects the amount you need to withdraw from a portfolio.
Key limitations of the 4% rule include: it was based on US historical data only; international returns have varied; today's starting valuations may imply lower forward returns; it does not account for flexible spending; and it assumed a 30-year retirement, not the 40-60 year horizons many early retirees face. A lower SWR of 3-3.5% is often recommended for longer retirements.
Healthcare before Medicare
One of the largest FIRE planning variables is healthcare costs between retirement and Medicare eligibility at age 65. ACA marketplace premiums, COBRA continuation coverage, and out-of-pocket costs can add $10,000-$30,000 per year for an individual, depending on age, income and plan. This calculator does not model healthcare costs separately; add them to your annual expenses figure to get a realistic FIRE number.
FIRE calculator: frequently asked questions
What is FIRE?
FIRE stands for Financial Independence, Retire Early. It is a personal finance movement built around accumulating enough invested assets that your portfolio can sustain your living expenses indefinitely, allowing you to retire far earlier than the traditional age. Followers typically aim to reduce expenses, maximise savings rate, and invest in low-cost index funds. The CFPB retirement planning tools at consumerfinance.gov cover the underlying savings and investment concepts.
What is the FIRE number?
Your FIRE number is the portfolio size you need to sustain your annual expenses indefinitely using a safe withdrawal rate. Using the 4% rule, the FIRE number equals your annual expenses divided by 0.04, which is the same as multiplying annual expenses by 25. For example, $50,000 per year in expenses requires a $1,250,000 portfolio. Adjusting the safe withdrawal rate changes this multiple: a 3.5% rate implies a 28.6x multiple.
What is the 4% rule, and is it still valid?
The 4% rule, derived from William Bengen's 1994 analysis of historical US market data, holds that a retiree can withdraw 4% of their initial portfolio per year (inflation-adjusted) for at least 30 years with a high historical success rate. The 'Trinity Study' (Cooley, Hubbard, Walz 1998) reached similar conclusions. Critics note that today's lower bond yields and higher valuations may reduce future returns, making 3% or 3.5% more conservative choices for longer retirements. The 4% rule is a starting guideline, not a guarantee.
How does inflation affect FIRE?
Inflation erodes the real value of your withdrawals over time. The 4% rule was designed to support inflation-adjusted withdrawals, meaning the withdrawal amount increases each year with inflation. In practice, many FIRE retirees use flexible spending strategies, cutting discretionary spending in down markets to protect the portfolio. The SSA's retirement planning resources at ssa.gov discuss how inflation interacts with fixed-income strategies.
What is the difference between lean FIRE and fat FIRE?
Lean FIRE refers to retiring early on a minimal budget, typically under $40,000 per year, requiring a smaller FIRE number and a higher savings rate. Fat FIRE involves retiring on a higher budget, often $80,000 per year or more, allowing more lifestyle flexibility but demanding a larger portfolio and longer accumulation phase. Barista FIRE and Coast FIRE are hybrid variants where part-time work or front-loaded saving reduces full portfolio dependence.
Should I consult a financial advisor for FIRE planning?
This calculator is a planning tool, not financial advice. FIRE planning involves many variables beyond this model: tax-efficient account sequencing (Roth conversions, IRA ladders), healthcare costs before Medicare eligibility, sequence of returns risk, and Social Security timing. A fee-only financial advisor (one who does not earn commissions) can model these interactions for your specific situation. The CFPB has guidance on choosing an advisor at consumerfinance.gov.
Official sources
- Retirement planning tools and concepts: CFPB, Retirement Tools
- SSA retirement age and benefit reduction: SSA, Retirement Planner: Full Retirement Age
- Choosing a financial advisor: CFPB, How do I choose a financial advisor?
Reviewed by the CalculatorHub team, edited by James Graham, 12 June 2026. See our methodology. General information, not financial advice.