About FIRE Calculator
The FIRE (Financial Independence, Retire Early) Calculator helps you determine the portfolio size needed to achieve financial independence using the safe withdrawal rate method. Based on the classic 4% rule popularized by the Trinity Study, your FIRE number is calculated as 25 times your annual spending. The tool projects your portfolio growth year by year using your current savings, monthly contributions, and expected annual return, showing exactly when your portfolio will reach your FIRE target. You can adjust variables like return rate, withdrawal rate, and spending to explore different scenarios, including Coast FIRE, Lean FIRE, or Fat FIRE approaches.
How to Use This Calculator
Enter your current age (30), your desired retirement age (also called FI age, say 45), your current savings ($75,000), your annual income ($100,000), your annual expenses ($55,000), your expected annual return rate (7% for a balanced portfolio), and your expected annual savings amount ($30,000). Click 'Calculate' to see your FIRE number (25x your annual expenses = $1,375,000), your projected savings at retirement age, your withdrawal rate, and whether you can retire early on schedule.
How to Interpret Your Results
Age 30, saving $30k/year of $100k income (30% savings rate), current savings $75k, target $1,375,000. At 7% returns, you'd reach FI in about 18 years, retiring at 48. Your savings grow to approximately $1,150,000 by age 48 — close but slightly short of your FIRE number. Increasing savings to $35k/year (35% rate) cuts the timeline to 16 years (retire at 46). The safe withdrawal rate of 4% on $1,150,000 gives $46,000/year — below your $55,000 expenses, meaning you need either more savings or lower expenses. Reducing expenses to $50k drops the FIRE number to $1,250,000, achievable by age 47.
When to Use This Calculator
Use this calculator when designing your early retirement plan to see if your current savings rate is on track. It's essential during annual financial reviews to adjust for changes in income, expenses, or market conditions. If you receive a raise or bonus, run the numbers to see how increasing your savings rate accelerates your FI date. The calculator is also useful when considering a career change or sabbatical — it shows how reducing income impacts your retirement timeline. Revisit quarterly to track progress toward your FIRE number.
Frequently Asked Questions
What is the 4% rule and does it still work?
The 4% rule (Trinity Study) states you can withdraw 4% of your portfolio in your first retirement year, adjusted for inflation each year, and have a 95% chance of your money lasting 30 years. Your FIRE number = annual expenses / 0.04 (or 25x expenses). For early retirees with 50+ year horizons, a more conservative 3-3.5% withdrawal rate is safer. Sequence of returns risk (a market crash in early retirement) is the biggest threat. Consider a flexible withdrawal strategy rather than sticking rigidly to 4% — reduce spending during down markets to protect your portfolio.
What is the difference between FIRE, Lean FIRE, and Fat FIRE?
Lean FIRE targets early retirement with a minimalist lifestyle, typically requiring a corpus of 25-30x annual expenses of around $30,000-$40,000 per year. Fat FIRE aims for a higher retirement lifestyle with $80,000-$100,000+ annual spending, requiring larger portfolios of $2.5 million or more. Traditional FIRE falls in between, usually targeting $40,000-$80,000 in annual spending. The approach you choose depends on your desired lifestyle and the trade-off between retiring earlier (Lean FIRE) versus living more comfortably in retirement (Fat FIRE).
How do I calculate my FIRE number?
Your FIRE number is calculated by dividing your annual retirement expenses by your safe withdrawal rate. Using the 4% rule, FIRE number = annual expenses x 25. For example, if you need $50,000 per year in retirement, your target corpus is $1.25 million. For a more conservative 3.5% withdrawal rate, multiply by 28.6 instead of 25. This calculation assumes your portfolio is invested in a balanced mix of stocks and bonds (typically 60-80% equities) and that returns will outpace inflation over the long term.
What is sequence of returns risk in early retirement?
Sequence of returns risk is the danger of experiencing poor investment returns in the early years of retirement while you are withdrawing money. If the market drops 20-30% in your first few years of retirement and you continue withdrawing, you lock in losses and deplete your portfolio faster. This risk is especially acute for early retirees with 40-50 year horizons. Strategies to mitigate it include maintaining a cash buffer of 2-3 years of expenses, using a flexible withdrawal strategy (reducing spending during downturns), and having a bond tent approach where you increase bond allocation just before retirement.
Should I include Social Security in my FIRE calculation?
Yes, Social Security should be factored into your FIRE plan, but conservatively. For early retirees, Social Security benefits won't start until age 62 at the earliest (full retirement age is 67 for most). You can model it as a future income stream that reduces the amount you need to withdraw from your portfolio in later years. A common approach is to calculate your FIRE number covering 100% of expenses until Social Security kicks in, then plan for Social Security to cover 25-40% of expenses thereafter. Always use reduced benefit estimates (75-80% of projected amounts) to account for potential future cuts.