Research shows that withdrawing 4% of your portfolio annually has historically lasted 30+ years. For longer retirements (40+ years), some use 3–3.5%.

How long does it take to reach FIRE?

It depends almost entirely on your savings rate. At a 10% savings rate, it takes approximately 40 years. At 50%, about 17 years. At 75%, roughly 7 years. Income level matters far less than the gap between income and spending.

What are the different types of FIRE?

Lean FIRE: retiring on $25,000–$40,000/year with minimal expenses. Regular FIRE: $50,000–$80,000/year. Fat FIRE: $100,000+/year. Barista FIRE: semi-retirement with part-time work covering basic expenses. Coast FIRE: having enough saved that growth alone reaches your FIRE number without additional contributions.

Is the FIRE calculator accurate for early retirement?

It uses the standard future value formula with your inputs and the 4% safe withdrawal rate. For retirements longer than 30 years, use 3.5% SWR (28.5× expenses) for a more conservative estimate. The calculator does not model sequence-of-returns risk or variable spending.

FIRE Calculator — Calculate Your Financial Independence Number & Retirement Date

Calculate your FIRE number and years to financial independence

Annual expenses ($)

What you spend per year in retirement

Current savings / investments ($)

Annual income ($)

Expected return: 7%

Safe withdrawal rate: 4%

4% rule is the standard

How to use FIRE Calculator

Free FIRE calculator. Enter annual expenses, current savings, and monthly contributions to calculate your FIRE number (25× expenses) and years to financial independence.

A FIRE calculator computes your Financial Independence, Retire Early number — the portfolio size at which you can stop working and live off investment returns indefinitely. Enter your annual expenses, current savings, monthly contribution, and expected investment return to see your FIRE number and how many years until you reach it. The FIRE movement is built on one core insight: financial independence is about your savings rate and spending level, not your income.

How to use this FIRE Calculator

1Enter your annual living expenses — the amount you spend per year in retirement. Be realistic; underestimating expenses is the most common FIRE planning mistake.
2Enter your current invested net worth (savings + brokerage + retirement accounts, excluding home equity).
3Enter your monthly savings and investment contribution.
4Enter your expected annual investment return. Most FIRE planners use 7% (inflation-adjusted S&P 500 historical average).
5The calculator shows your FIRE number (25× expenses at 4% SWR), current savings rate, and years to financial independence.

How to calculate your FIRE number

Your FIRE number is the portfolio size that generates enough annual returns to cover your expenses indefinitely using the 4% safe withdrawal rate, derived from the Trinity Study. At 4% withdrawal, a diversified portfolio has historically sustained 30+ year retirements across all historical market periods.

FIRE Number = Annual Expenses × 25

Variable	Meaning
FIRE Number	Annual expenses ÷ safe withdrawal rate (0.04)
25× rule	Shorthand for the 4% withdrawal rate (1 ÷ 0.04 = 25)
Savings rate	(Income − Expenses) ÷ Income × 100
Years to FIRE	Calculated using future value of current savings + ongoing contributions
SWR	Safe Withdrawal Rate — typically 3.5–4% for traditional FIRE, 3–3.5% for early retirees

Financial independence calculator example: $50,000 annual expenses, $150,000 saved

01Annual expenses: $50,000. FIRE number: $50,000 × 25 = $1,250,000.
02Current savings: $150,000. Monthly contribution: $2,500 ($30,000/year). Annual return: 7%.
03Savings rate: If income is $80,000 and expenses are $50,000, savings rate = ($80,000 − $50,000) ÷ $80,000 = 37.5%.
04Future value calculation: growing $150,000 at 7% plus $30,000/year contributions.
05Result: approximately 18 years to reach $1,250,000.

Result

FIRE number: $1,250,000. Years to FIRE at current pace: ~18 years. Increasing monthly savings from $2,500 to $3,500 reduces timeline to ~15 years.

What affects your FIRE number and timeline?

Annual expenses

The most powerful lever. Reducing annual spending from $60,000 to $50,000 lowers your FIRE number by $250,000. Every $1,000 reduction in annual spending saves $25,000 in required portfolio size.

Savings rate

Research by Mr. Money Mustache and others shows that a 50% savings rate leads to FIRE in approximately 17 years from zero. A 75% savings rate gets there in about 7 years, regardless of income level.

Investment return

The difference between 6% and 8% annual returns on a $1,000,000 portfolio is $20,000/year — a significant impact on how long your money lasts in early retirement.

Safe withdrawal rate

The traditional 4% rule was derived for 30-year retirements. For retirements of 40–50+ years (common in FIRE), many practitioners use 3–3.5% SWR, which increases the FIRE number to 28–33× expenses.

Current portfolio size

Compounding works faster on larger bases. Someone with $500,000 saved grows their portfolio much faster in absolute dollars than someone starting from $50,000, even at the same savings rate.

Healthcare costs

Early retirees must account for private health insurance before Medicare eligibility at 65. This can add $500–$1,500/month to expenses, significantly raising the FIRE number.

Tips and things to know

✓Reducing spending has a double impact: it lowers your FIRE number AND increases your savings rate — a $10,000 annual spending cut gets you to FIRE years faster through both effects simultaneously.
✓The 4% rule was designed for 30-year retirements. If you plan to retire at 40, consider using a 3.5% withdrawal rate, making your FIRE number 28.5× annual expenses.
✓Tax-advantaged accounts (401k, Roth IRA, HSA) are critical for FIRE — the Roth conversion ladder and 72(t) SEPP rules allow penalty-free access before age 59½.
✓Sequence-of-returns risk is the biggest FIRE threat: retiring into a bear market can deplete a portfolio faster than the historical simulations suggest. Keep 1–2 years of expenses in cash.
✓Geo-arbitrage — moving to a lower cost-of-living area or country after reaching FIRE — can dramatically extend portfolio longevity or allow retiring with a smaller nest egg.

Official resources and further reading

Trinity Study — Portfolio Success Rates (1998)

The original academic paper by Cooley, Hubbard, and Walz that established the 4% safe withdrawal rate through historical portfolio analysis.

SEC Investor.gov — Retirement Planning

SEC guidance on investment basics, compound growth, and building a long-term portfolio for financial independence.

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