What is FIRE?
FIRE — Financial Independence, Retire Early — is a strategy where you save and invest aggressively (usually 50-70% of your income) so you can stop working decades before the typical retirement age. The core idea is simple: accumulate 25 times your annual expenses in invested assets, then live off 4% per year.
That 4% number comes from the Trinity Study, a 1998 research paper that analyzed rolling 30-year periods in U.S. market history. It found that a 4% initial withdrawal rate (adjusted for inflation each year) had a very high success rate — meaning the portfolio survived in nearly all historical scenarios.
FIRE isn't about deprivation. It's about having the option to choose whether you work, rather than being forced to. Some people hit FIRE and never work again. Others switch to part-time work, start a business, or take lower-paying jobs they actually enjoy. The point is having the freedom to decide.
How the Calculator Works
This calculator takes your current age, net worth, income, and savings rate, then projects your portfolio growth year by year until you hit your FIRE number. It accounts for compound returns, inflation, and different withdrawal rates.
FIRE Number = Annual Expenses × 25
Annual Expenses = Annual Income × (1 − Savings Rate)
Safe Withdrawal Rate = 4% (Trinity Study baseline)
If you spend $60,000 per year, your FIRE number is $1.5M ($60K × 25). If you can live on $40,000 per year, it drops to $1M. The lower your expenses, the faster you get there — that's why savings rate is the most important variable.
Types of FIRE
FIRE isn't one-size-fits-all. There are several flavors depending on how much you want to save and what kind of retirement lifestyle you're aiming for.
Full FIRE
Your FIRE number = Annual expenses × 25. At this point, you can safely withdraw 4% per year and never run out of money. This is true financial independence — no work required.
Coast FIRE
You've saved enough that compound growth alone will get you to FIRE by traditional retirement age. You only need to cover current expenses — no more aggressive saving required. For example, $200K invested at age 30 with 7% returns becomes ~$1.5M by age 65.
Barista FIRE
You have enough to cover most expenses but work part-time for benefits (especially health insurance) and extra cash. Think 20 hours/week at a job you actually enjoy.
Lean FIRE
FIRE on a budget — typically under $40,000/year in expenses. Lower FIRE number ($1M or less), but you're living more minimally. Popular in low-cost-of-living areas or with paid-off housing.
Fat FIRE
FIRE with a bigger budget — $100,000+/year in expenses. Higher FIRE number ($2.5M+), but you get to keep your current lifestyle in retirement. No compromising on travel, dining, or housing.
Savings Rate vs. Years to FIRE
Your savings rate is the single biggest factor in when you can retire. This table assumes you're starting from zero, earning a 7% real return (after inflation). The math is based on the savings rate formula from the FIRE community.
| Savings Rate | Years to FIRE | Retire At (starting at 25) | What It Means |
|---|---|---|---|
| 10% | 51 years | 76 | Essentially traditional retirement |
| 20% | 37 years | 62 | A bit early, but not dramatically |
| 30% | 28 years | 53 | Retire in your early 50s |
| 40% | 22 years | 47 | Solidly early retirement |
| 50% | 17 years | 42 | The FIRE sweet spot for many |
| 60% | 12.5 years | 37.5 | Aggressive but achievable |
| 70% | 8.5 years | 33.5 | Extremely aggressive saving |
| 80% | 5.5 years | 30.5 | Requires very high income or very low expenses |
Based on 7% real annual return. Starting from zero savings. Formula: Years = ln(savings rate / (1 − savings rate) × return + 1) / ln(1 + return).
FIRE Number by Annual Expenses
Your FIRE number scales directly with your annual spending. This table shows the 25× target for common expense levels. Remember — this is what you need invested, not including home equity or other non-investable assets.
| Annual Expenses | FIRE Number (25×) | Monthly Withdrawal (4%) | Lifestyle |
|---|---|---|---|
| $25,000 | $625,000 | $2,083 | Lean FIRE, very frugal |
| $30,000 | $750,000 | $2,500 | Lean FIRE, paid-off house |
| $40,000 | $1,000,000 | $3,333 | Comfortable lean FIRE |
| $50,000 | $1,250,000 | $4,167 | Moderate lifestyle |
| $60,000 | $1,500,000 | $5,000 | Suburban family lifestyle |
| $80,000 | $2,000,000 | $6,667 | Comfortable middle-class |
| $100,000 | $2,500,000 | $8,333 | Upper middle-class |
| $120,000 | $3,000,000 | $10,000 | Comfortable Fat FIRE |
| $150,000 | $3,750,000 | $12,500 | Fat FIRE, premium lifestyle |
Investment Growth Over Time
How fast your money grows depends on how much you invest each month and your annual return. This table shows the power of consistent investing — starting from zero, with returns compounded monthly.
| Monthly Investment | 5% Return (10 yr) | 7% Return (10 yr) | 7% Return (20 yr) | 7% Return (30 yr) |
|---|---|---|---|---|
| $500 | $77K | $87K | $261K | $613K |
| $1,000 | $155K | $173K | $521K | $1.23M |
| $1,500 | $232K | $260K | $782K | $1.84M |
| $2,000 | $310K | $347K | $1.04M | $2.45M |
| $3,000 | $465K | $520K | $1.56M | $3.68M |
| $5,000 | $775K | $867K | $2.61M | $6.13M |
Values include compounded returns only (no inflation adjustment). Your actual returns will vary based on market conditions and asset allocation.
Practical Example
Sarah, age 30, earns $90,000/year and saves 40% of her income. She has $80,000 already invested in index funds.
- Annual expenses: $90,000 × (1 − 0.40) = $54,000
- FIRE number: $54,000 × 25 = $1,350,000
- Monthly investment: $90,000 × 0.40 ÷ 12 = $3,000/month
- Starting portfolio: $80,000
At 7% real annual return, her $80K grows to ~$610K in 30 years on its own. But with $3,000/month added consistently, she hits $1.35M in approximately 15 years — retiring at age 45.
If she bumps her savings rate to 50% ($4,500/month, $45K expenses), she hits $1.125M (her new FIRE number) in about 10 years — retiring at 40.
Safe Withdrawal Rates by Retirement Length
The 4% rule assumes a 30-year retirement. If you retire at 35, you might need your money to last 50+ years. Here's how different withdrawal rates perform over different time horizons, based on historical U.S. market data.
| Withdrawal Rate | 30-Year Success | 40-Year Success | 50-Year Success |
|---|---|---|---|
| 3.0% | 100% | 100% | ~98% |
| 3.5% | 100% | ~96% | ~90% |
| 4.0% | ~95% | ~85% | ~75% |
| 4.5% | ~85% | ~70% | ~55% |
| 5.0% | ~75% | ~50% | ~35% |
Success = portfolio survived the entire period without running out of money. Based on historical U.S. stock/bond returns from 1871–2020. Early retirees should consider 3.5% or lower for extra safety.
Real-World FIRE Scenarios
Here are three realistic paths to FIRE, each with different trade-offs between lifestyle and speed.
Scenario A: Dual Income, No Kids — Aggressive
Combined income: $160K. Savings rate: 55%. Current savings: $120K. Annual expenses: $72K.
- FIRE number: $1.8M
- Monthly investment: $7,333
- Time to FIRE: ~9 years (retire at 37)
- Strategy: Max both 401(k)s ($47K/yr), Roth IRAs ($14K/yr), rest in taxable brokerage
Scenario B: Single Income, One Kid — Moderate
Income: $110K. Savings rate: 35%. Current savings: $60K. Annual expenses: $71.5K.
- FIRE number: $1.79M
- Monthly investment: $3,208
- Time to FIRE: ~16 years (retire at 46)
- Strategy: Max 401(k), backdoor Roth, 529 plan for kid, taxable brokerage for remainder
Scenario C: Coast FIRE — Conservative
Income: $75K. Savings rate: 20%. Current savings: $150K (at age 30). Annual expenses: $60K.
- Coast FIRE number: ~$150K at age 30 (already there!)
- Full FIRE number: $1.5M
- Strategy: Stop aggressive saving. Switch to part-time or lower-stress job. Let compound growth handle the rest.
- By age 65: $150K → ~$1.14M at 7% return (without any additional contributions)
Common FIRE Mistakes
The FIRE path has real pitfalls. Here are the most common ones and how to avoid them.
Overestimating your returns
The S&P 500 averages ~10% nominally, but after inflation it's ~7%. Plan using real returns (after inflation), not nominal. Some people also forget that a 60/40 portfolio returns less than 100% stocks.
Ignoring healthcare costs
Before Medicare kicks in at 65, you need to fund your own health insurance. A marketplace plan can cost $500-$1,500/month depending on state and income. Factor this into your FIRE number.
Being too aggressive with withdrawal rate
4% works for 30-year retirements. If you retire at 35, your money needs to last 50+ years. Consider 3.5% or even 3% for extra safety. Build in a buffer.
Forgetting about taxes
Withdrawals from traditional 401(k)s and IRAs are taxed as ordinary income. Roth accounts are tax-free. Taxable brokerage accounts have capital gains tax. Plan your withdrawal strategy across account types.
Lifestyle inflation eating your raises
When your income goes up, your spending often follows. This is the #1 killer of FIRE timelines. When you get a raise, keep your spending flat and invest the difference.
No emergency fund
Before going all-in on FIRE investing, keep 3-6 months of expenses in cash. Without this, a job loss or medical emergency forces you to sell investments at the worst time.
Disclaimer
This calculator provides estimates based on historical returns and the 4% safe withdrawal rule. Past performance does not guarantee future results. Actual returns, inflation, taxes, and personal circumstances will vary.
This tool is for educational purposes only — not financial advice. Consult a qualified financial advisor before making retirement decisions. The 4% rule may not be suitable for retirements lasting 40+ years; early retirees should consider lower withdrawal rates.