FIRE Number Calculator
Find out how large your portfolio needs to be to retire and live off investment returns. Read the guide →
For educational purposes only. Calculator results are estimates based on the inputs you provide and are not a substitute for professional financial advice. Consult a licensed financial advisor before making investment, borrowing, or retirement decisions.
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What is a FIRE number?
FIRE stands for Financial Independence, Retire Early. Your FIRE number is the total investment portfolio size you need to sustain your lifestyle indefinitely without working. Once you reach it, your investments generate enough returns to cover your annual spending — and theoretically last forever.
The concept is rooted in the Trinity Study, a landmark 1998 paper by three finance professors at Trinity University that analysed historical US market data to determine how much you can withdraw annually without depleting your portfolio. Their conclusion — the now-famous 4% rule — became the foundation of the FIRE movement.
How to use this calculator
- Annual Expenses in Retirement — Enter how much you expect to spend per year in retirement. Use your current spending as a starting point, then adjust for anticipated lifestyle changes.
- Safe Withdrawal Rate — Choose a withdrawal rate. The classic 4% rate is based on 30-year retirement horizons. If you plan to retire early (40+ year horizon), many advisors recommend 3–3.5%.
- Click Calculate to see your FIRE number and a comparison table across withdrawal rates.
The 4% rule explained
The 4% rule states that if you withdraw 4% of your portfolio in the first year of retirement, then adjust that amount for inflation each subsequent year, your portfolio has a high probability of lasting at least 30 years — even through market downturns.
The calculation is simple: FIRE Number = Annual Expenses ÷ Withdrawal Rate. At $60,000/year and a 4% rate, you need $1,500,000. At 3.5%, you need $1,714,286. Lower withdrawal rates require larger portfolios but provide greater security for longer retirements.
Frequently asked questions
Is the 4% rule still valid today?
The 4% rule was based on historical US market data through the 1990s. Many financial researchers now suggest 3–3.5% for early retirees facing 40–50 year horizons, or for those retiring during periods of high valuations and low bond yields. The rule is a useful starting point, not a guarantee.
What assets count toward my FIRE number?
Generally: investable assets — brokerage accounts, IRAs, 401ks, index funds, and similar. Home equity is typically excluded unless you plan to downsize. Social Security or pension income can reduce the portfolio size needed by reducing your annual spending requirement.
How long will it take me to reach my FIRE number?
This depends on your savings rate and investment returns. The higher your savings rate, the faster you accumulate. At a 50% savings rate, most people can reach FIRE in roughly 15–17 years regardless of income level, according to Mr. Money Mustache's famous analysis.
Should I include Social Security in my retirement plan?
If you plan to retire early (before 62–67), you cannot claim Social Security immediately, so plan without it. If you retire at or near traditional retirement age, you can reduce your required FIRE number by the annual Social Security benefit you expect to receive.
Real FIRE number examples
Annual expenses of $60,000 — how large does your portfolio need to be?
Using the 4% rule, spending $60,000 per year in retirement requires a portfolio of $1,500,000. At a 3.5% withdrawal rate — more conservative for early retirees — the target rises to $1,714,286. The difference highlights how significantly your withdrawal rate assumption affects the final number.
Can I retire at 45 with $800,000 saved and $50,000 in annual expenses?
A $50,000 annual spending target requires $1,250,000 under the 4% rule. With $800,000 saved, you have 64% of your target. To close the gap in 10 years at a 7% annual return, you would need to invest approximately $2,400 per month — a high but achievable savings rate for a dual-income household.
Lean FIRE at $40,000/year vs Fat FIRE at $100,000/year
Lean FIRE on $40,000 in annual expenses requires a $1,000,000 portfolio. Fat FIRE on $100,000/year requires $2,500,000 — 2.5x the portfolio but enabling a much more comfortable retirement with travel, home upgrades, and unexpected costs. Most people target somewhere in between.
How part-time income changes everything
Earning even $20,000 per year in retirement from consulting, freelancing, or part-time work dramatically lowers the portfolio you need. If you spend $70,000 but earn $20,000 on the side, your portfolio only needs to cover $50,000 — requiring $1,250,000 instead of $1,750,000. A small income stream can mean retiring years earlier.