FIRE Calculator (Financial Independence & Retire Early)

FIRE—Financial Independence, Retire Early—is more than a financial strategy; it's a movement that has transformed how millions of people think about work, money, and life. The core idea is simple: save aggressively, invest wisely, and reach the point where your investments can sustain your lifestyle indefinitely. At that point, work becomes optional. You can retire in your 30s, 40s, or 50s—decades earlier than traditional retirement.

But here's what most people get wrong about FIRE: it's not about extreme frugality or getting rich quick. It's about intentionality—understanding exactly how much money you need to be free, then building a plan to get there. This calculator helps you determine your "FIRE number" (the portfolio size that sustains your lifestyle), estimate when you'll reach it based on your current savings rate, and see whether you're on track or need to adjust.

Whether you're pursuing Lean FIRE (low expenses, smaller portfolio), Fat FIRE (higher lifestyle, larger portfolio), Coast FIRE (reach a point where you can stop contributing and let growth do the work), or traditional FIRE, this calculator adapts to your goals. Enter your numbers, adjust the assumptions, and see a realistic projection of your path to financial freedom.

The power of FIRE isn't just about retiring early—it's about having options. Financial independence means you can choose to work on projects you love, take time for family, travel, or simply escape the stress of living paycheck to paycheck. This calculator shows you what's possible.

What Is Your FIRE Number?

Your FIRE number is the total investment portfolio value you need to sustain your lifestyle indefinitely. It's calculated using your annual spending and a safe withdrawal rate (typically 4%). The formula is straightforward:

Example: If you spend $50,000/year and use a 4% withdrawal rate, your FIRE number is $50,000 ÷ 0.04 = $1,250,000. This is often called the "25x rule"—you need 25 times your annual spending saved.

The 4% Rule Explained

The 4% rule comes from the Trinity Study, which analyzed historical market returns and found that a 4% annual withdrawal rate had a high probability of lasting 30+ years. If you have $1,000,000, you can withdraw $40,000/year (adjusted for inflation) with reasonable confidence your money won't run out. However, this is a guideline, not a guarantee—market conditions matter.

Types of FIRE

• Lean FIRE: Lower spending (~$25,000-$40,000/year), smaller portfolio needed, more frugal lifestyle
• Traditional FIRE: Moderate spending (~$40,000-$80,000/year), balanced approach
• Fat FIRE: Higher spending (~$100,000+/year), larger portfolio needed, comfortable lifestyle
• Coast FIRE: Save enough early that compound growth alone will fund retirement—you can stop contributing and let it grow
• Barista FIRE: Reach partial FI, then work a low-stress job for benefits and supplemental income

Why Savings Rate Matters More Than Income

A common FIRE insight: your savings rate determines how fast you reach FI more than your income level. Someone earning $60,000 who saves 50% ($30,000/year) will reach FI faster than someone earning $150,000 who saves 15% ($22,500/year). High savings rate also means lower spending, which means a lower FIRE number.

The Role of Investment Returns

Your portfolio must grow faster than inflation for FIRE to work. Historical stock market returns average ~7% after inflation, but actual returns vary year to year. This calculator uses your assumed return rate to project growth—but remember, these are projections based on assumptions, not guarantees.

Step 1: Enter Your Current Age and Target FI Age

Input your current age and the age you hope to reach financial independence. This sets the timeline for calculations. Don't know your target age? Try different scenarios to see how changing your target affects what you need to save.

Step 2: Enter Your Current Portfolio Balance

Input the total value of your investment accounts (401k, IRA, brokerage accounts, etc.). This is your starting point. If you're just starting out, enter $0—the calculator will show you what consistent saving can build.

Step 3: Set Your Monthly Contribution

Enter how much you contribute to investments each month. This includes 401k contributions, IRA deposits, and brokerage investing. The higher this number, the faster you reach FI. Try adjusting it to see how increased savings accelerates your timeline.

Step 4: Set Return and Inflation Assumptions

Enter your expected annual investment return (historical average: ~7% real returns for stocks) and inflation rate (typically ~2-3%). The calculator uses these to project portfolio growth and adjust spending for inflation. Be conservative—lower return assumptions create more realistic projections.

Step 5: Enter Your Annual Spending

Input your current annual spending. This determines your FIRE number. Include everything: housing, food, transportation, healthcare, entertainment, travel. Don't underestimate— realistic spending projections prevent unpleasant surprises.

Step 6: Set Your Safe Withdrawal Rate

Choose your withdrawal rate (default: 4%). Lower rates (3-3.5%) are more conservative; higher rates (4.5-5%) are riskier but require smaller portfolios. Your choice depends on your risk tolerance and retirement timeline length.

Step 7: Include Other Income (Optional)

If you'll have other income sources in retirement (Social Security, pension, rental income, part-time work), enter them here. This reduces how much your portfolio needs to cover, effectively lowering your FIRE number.

Calculating Your FIRE Number

The basic formula is simple:

Example: $60,000 spending, $15,000 Social Security, 4% SWR = ($60,000 - $15,000) ÷ 0.04 = $1,125,000 FIRE number.

Portfolio Growth Projection

The calculator projects how your portfolio grows using compound growth with contributions:

Where P = current portfolio, r = annual return rate, n = years, C = annual contributions. This shows how your current savings plus ongoing contributions grow over time.

Inflation-Adjusted Spending

The calculator can adjust your spending for inflation, showing what you'll need in future dollars. $50,000 today at 2.5% inflation becomes ~$64,000 in 10 years and ~$82,000 in 20 years. This affects your future FIRE number.

Savings Rate and Time to FI

There's a powerful relationship between savings rate and years to FI:

• 10% savings rate → ~51 years to FI
• 25% savings rate → ~32 years to FI
• 50% savings rate → ~17 years to FI
• 75% savings rate → ~7 years to FI

This assumes 5% real returns and starting from zero. Higher savings rates dramatically accelerate your timeline.

Scenario 1: Young Professional Starting from Zero

Profile: Alex, 25, earns $65,000. Currently has $0 saved. Spends $35,000/year. Can save $2,000/month.

Analysis: FIRE number at 4% SWR: $875,000. Saving $24,000/year at 7% returns, Alex reaches FI at age 42 (17 years). If Alex increases savings to $2,500/month after raises, FI comes at 39.

Takeaway: Starting young with aggressive savings creates a clear path to FI in your early 40s—even without a massive income.

Scenario 2: Dual-Income Couple Pursuing Fat FIRE

Profile: Jordan and Taylor, both 32, combined income $200,000. Current portfolio: $250,000. Spending: $100,000/year (they want a comfortable lifestyle). Save $5,000/month combined.

Analysis: Fat FIRE number at 4% SWR: $2,500,000. With $250,000 starting and $60,000/year contributions at 7% returns, they reach FI at age 51 (19 years).

Takeaway: Fat FIRE is achievable but requires patience. If they reduce spending to $80,000/year (FIRE number: $2M), they reach FI at 48.

Scenario 3: Late Starter Playing Catch-Up

Profile: Sam, 45, discovered FIRE recently. Current portfolio: $300,000. Spending: $55,000/year. Can now save $3,500/month after cutting expenses.

Analysis: FIRE number: $1,375,000. Starting at $300,000 with $42,000/year contributions at 7% returns, Sam reaches FI at age 60 (15 years).

Takeaway: Starting at 45 still allows for early retirement (vs. 67+). The $300,000 head start helps significantly.

Scenario 4: Coast FIRE Strategy

Profile: Morgan, 30, has saved aggressively and has $250,000 invested. Planning to Coast FIRE—let the portfolio grow without contributions until traditional retirement at 60.

Analysis: $250,000 at 7% real returns for 30 years = ~$1.9 million. At 4% SWR, this supports $76,000/year spending. Morgan can stop aggressive saving and work a lower-stress job.

Takeaway: Coast FIRE offers work flexibility now while ensuring traditional retirement is fully funded.

Scenario 5: Lean FIRE Minimalist

Profile: Casey, 28, earns $50,000 but lives frugally—spending only $22,000/year. Saves $1,500/month. Current portfolio: $40,000.

Analysis: Lean FIRE number: $550,000. Starting at $40,000 with $18,000/year contributions at 7% returns, Casey reaches FI at age 41 (13 years).

Takeaway: Lean FIRE is the fastest path to FI. Low spending means both lower savings needed and higher savings rate.

• ❌ Underestimating spending: The most dangerous FIRE mistake. If your actual spending is higher than projected, your FIRE number is too low, and you risk running out of money. Track spending carefully and add a buffer.
• ❌ Using overly optimistic return assumptions: Assuming 10%+ annual returns sets you up for disappointment. Use conservative estimates (5-7% real returns). If markets outperform, you'll reach FI sooner—a pleasant surprise.
• ❌ Ignoring healthcare costs: In the US, healthcare before Medicare (age 65) is expensive. A family can easily spend $15,000-$25,000/year on premiums and out-of-pocket costs. Factor this into your spending projections.
• ❌ Forgetting about taxes: Withdrawals from traditional 401k/IRA accounts are taxable income. Your $40,000 withdrawal might require $45,000+ gross to net $40,000 after taxes. Tax-efficient withdrawal strategies matter.
• ❌ Not adjusting for lifestyle changes: Your spending at 55 may differ from spending at 75. Early retirement often includes more travel; later years may have higher healthcare costs. Model different phases.
• ❌ Assuming a fixed withdrawal rate forever: The 4% rule is a starting point, not a rigid law. Flexible withdrawal strategies (reducing spending in down markets) improve portfolio survival rates significantly.
• ❌ Neglecting sequence of returns risk: A market crash in your first few years of retirement is more damaging than one later. Consider keeping 2-3 years of expenses in cash/bonds to avoid selling stocks in a downturn.

1. Geographic Arbitrage

Earn in high-income areas, then retire to lower cost-of-living locations. Your FIRE number in Thailand, Portugal, or even a US small town could be 40-60% lower than in San Francisco or NYC. Some FIRE practitioners move abroad to stretch their portfolios.

2. Tax Optimization Across Account Types

Build a ladder: Roth IRA for tax-free withdrawals after 59½, Traditional 401k/IRA for early retirement (via Roth conversion ladder or 72(t) SEPP), taxable brokerage for flexibility. This optimizes taxes over your entire retirement, potentially saving hundreds of thousands.

3. Variable Withdrawal Strategies

Instead of fixed 4% withdrawals, use guardrails: withdraw more in good market years, less in bad years. The Guyton-Klinger guardrails and VPW (Variable Percentage Withdrawal) methods can increase safe withdrawal rates to 5%+ with flexibility.

4. Building Income Streams Post-FI

Many FIRE achievers don't fully stop working—they pursue passion projects that generate some income: consulting, freelancing, content creation, rental properties. Even $10,000- $20,000/year from side work dramatically reduces portfolio withdrawal needs.

5. Front-Loading Savings

Save aggressively early in your career when expenses are lower (before kids, mortgage, etc.). The money you invest at 25 has 40+ years to compound—it's worth far more than money invested at 45. Prioritize savings rate in your 20s and 30s.

6. House Hacking for Reduced Expenses

Buy a duplex/triplex, live in one unit, rent others. The rental income covers your mortgage (or most of it), dramatically reducing housing costs and accelerating savings. Real estate can also provide post-FI income streams.

7. Health Savings Account (HSA) Triple Tax Advantage

Max out your HSA if eligible. Contributions are pre-tax, growth is tax-free, and withdrawals for medical expenses are tax-free. After 65, it works like a traditional IRA for non-medical expenses. It's the ultimate FIRE account for healthcare funding.