Find your Financial Independence number, years to retirement, and the exact savings rate that gets you there. Supports lean FIRE, regular FIRE, and fat FIRE targets.
FIRE Number
$0
Target portfolio size
Years to FIRE
—
Projected year
Monthly to Invest
$0
At current savings rate
Safe Withdrawal
4.0%
Annual from portfolio
Progress to FIRE0% — $0 saved
0%
Your Finances
$
$
$
1%90%
$
Assumptions
1%15%
0%8%
2%6%
Portfolio Growth to FIRE
How to use this calculator
01
Enter your retirement spending. Be honest about what you actually spend today. Many FIRE seekers optimise spending alongside saving — even trimming $500/month from spending reduces your FIRE number by $150,000.
02
Enter your current savings. Include all invested assets — 401(k), IRA, brokerage accounts, HSA. Don't include your home equity unless you plan to sell it.
03
Set your income and savings rate. Your savings rate is the single most powerful lever. Moving from 20% to 40% doesn't just double your accumulation speed — it also halves your spending baseline, reducing the FIRE number you need to hit.
04
Review the milestones. The 25%, 50%, and 75% markers show intermediate targets. Reaching 25% of your FIRE number is a huge psychological milestone — you're already partially financially independent.
05
Adjust the safe withdrawal rate. The classic 4% rule is based on 30-year retirements. If you plan to retire for 40+ years (early retirement), consider 3.5% or 3%. This increases your required portfolio but greatly reduces sequence-of-returns risk.
🎯 Planning FIRE? Model your retirement income in detail.
FIRE stands for Financial Independence, Retire Early. It is a personal finance movement built around the idea that aggressive saving and investing during your working years can allow you to retire decades earlier than the traditional age 65. The movement gained mainstream attention through blogs like Mr. Money Mustache and books like Your Money or Your Life. While early retirement is the headline, most FIRE adherents are primarily motivated by financial independence — the freedom to choose how you spend your time, regardless of whether you stop working entirely.
The 4% Rule and Safe Withdrawal Rate
The cornerstone of FIRE math is the 4% rule, derived from the Trinity Study — a 1998 analysis of historical stock and bond returns. The study found that a portfolio invested 50-75% in stocks could sustain annual withdrawals of 4% of the initial balance for at least 30 years in 95%+ of historical scenarios. This means your FIRE number is approximately 25x your annual expenses. If you spend $50,000/year, you need $1.25 million invested to retire safely.
FIRE Variants
Fat FIRE targets a high-spending retirement lifestyle — typically $80,000+/year — requiring a larger portfolio. Lean FIRE involves retiring on a very frugal budget, often $25,000-40,000/year for a couple. Barista FIRE involves retiring from a demanding career but continuing to do part-time or lower-stress work that covers day-to-day expenses while the portfolio continues to grow. Coast FIRE is the point where you have invested enough that compound growth alone will reach your FIRE number by traditional retirement age — no further contributions needed.
The most important variable in FIRE planning is your savings rate, not your income. Someone earning $60,000 and saving 50% will reach FIRE before someone earning $120,000 and saving 10%. The single most powerful lever is reducing expenses — every dollar you cut reduces both the amount you need to save and the amount your portfolio needs to support in retirement.
Frequently Asked Questions
What is the FIRE number? ▾
Your FIRE number is the total investment portfolio needed to fund your retirement indefinitely. It is calculated by multiplying your annual expenses by 25 (the inverse of the 4% safe withdrawal rate). If you spend $50,000 per year, your FIRE number is $1.25 million.
What is the 4% rule? ▾
The 4% rule states that you can safely withdraw 4% of your portfolio each year in retirement without running out of money over a 30-year period. It comes from the Trinity Study (1998), which analysed historical US market returns. Many FIRE adherents use 3.5% or 3% for longer retirements.
What is lean FIRE vs fat FIRE? ▾
Lean FIRE means retiring on a minimal budget (typically under $40,000/year). Regular FIRE targets average spending. Fat FIRE means retiring with enough to maintain a comfortable or luxurious lifestyle, typically $100,000+ per year. Your FIRE number scales with your target spending.
How does savings rate affect time to FIRE? ▾
Savings rate is the single most powerful lever for reaching FIRE. At a 10% savings rate, it takes about 40 years to retire. At 50%, about 17 years. At 75%, about 7 years. Higher savings rates work doubly: you accumulate wealth faster AND lower your spending baseline, which means a smaller FIRE number.
What investment return should I assume? ▾
Most FIRE calculators use 7% nominal or 5% real (inflation-adjusted) return, based on long-run US stock market averages. For a conservative estimate, use 5–6% nominal. Your actual return will depend on asset allocation — a 100% stock portfolio historically returns more than a bond-heavy one, but with higher volatility.
Does this calculator account for Social Security? ▾
Yes — enter your expected Social Security or pension income in the "Other annual income in retirement" field. This reduces the amount you need to withdraw from your portfolio, which lowers your FIRE number and accelerates your timeline.