FIRE Planning Tool
Calculate your Financial Independence number, project your retirement date, and model how changing your savings rate reshapes your entire timeline.
Written by Mike Starr
Founder, StackedTomorrow · M.S. Organizational Management
Last Reviewed: August 2026
Educational Content Only. All content on this page is provided for informational and educational purposes only. It does not constitute financial, investment, legal, tax, or retirement advice. The calculators and projections shown are illustrative models — not predictions or guarantees of future performance. Past performance does not guarantee future results. Always consult a qualified financial professional before making investment or retirement decisions.
Find your number and your date — the day you walk away from work, forever.
FIRE formula: 25× annual expenses. Withdraw 4% per year.
🎯 Your future self retires at age 52 — 22 years from now.
Potential for financial independence — your money works for you.
The green line is your FIRE target. Once your portfolio crosses it, you're financially free — your investments generate more than you spend, forever.
Financial Independence, Retire Early (FIRE) is built on one foundational concept: if your investment portfolio is large enough, its returns can fund your living expenses indefinitely — without you ever needing to work again. The number that represents this threshold is your FIRE number.
The standard FIRE number formula is elegantly simple: Annual Expenses × 25. If you spend $48,000 per year, your FIRE number is $1,200,000. Spend $72,000 per year? Your target is $1,800,000. The multiplier of 25 is derived directly from the 4% Rule — landmark research from William Bengen (1994) and the Trinity Study (1998) showing that a 4% annual withdrawal has historically sustained portfolios for 30+ year retirements with high success rates across most historical market conditions.
For early retirees planning a 40–50 year retirement (rather than the 30-year window the original research modeled), many FIRE practitioners use a more conservative 3–3.5% withdrawal rate, which corresponds to a FIRE number of 28.5–33x annual expenses. This builds additional safety margin for the extended time horizon and uncertainty of early retirement.
The calculator uses compound interest projections to model how your current savings and regular contributions grow toward your FIRE number over time. Key inputs:
Annual Expenses: Your total yearly spending — the primary driver of your FIRE number. Reducing expenses is the lever that simultaneously lowers your FIRE target and increases your savings rate.
Current Savings: Your current investable portfolio. Money already invested has compounding working in your favor immediately.
Monthly Contributions: How much you add to investments each month. Consistency here matters enormously over multi-decade timelines.
Expected Return: The annual return rate. The default 7% reflects inflation-adjusted historical U.S. equity returns. Adjust this based on your actual portfolio composition.
The output shows your projected FIRE date, total portfolio at independence, and a year-by-year growth chart — so you can see the compound growth curve and identify inflection points.
Savings rate is the single most powerful variable in your FIRE plan. It affects your timeline from both sides simultaneously: a higher savings rate means you're investing more (faster portfolio growth) and spending less (lower FIRE number target). The table below shows estimated years to FIRE starting from zero, assuming a 7% real return:
| Savings Rate | Approximate Years to FIRE |
|---|---|
| 10% | 43 years |
| 20% | 37 years |
| 30% | 28 years |
| 40% | 22 years |
| 50% | 17 years |
| 60% | 12 years |
| 70% | 8.5 years |
Source: Estimates based on standard compound interest projections. Real outcomes vary based on return rates, tax strategy, and lifestyle costs. Starting with savings already invested accelerates all timelines.
Lean FIRE
Annual spending under ~$40,000. Smaller portfolio required, faster timeline, requires frugal lifestyle.
Regular FIRE
Annual spending $40,000–$80,000. Balanced approach most FIRE community members pursue.
Fat FIRE
Annual spending $80,000+. Full lifestyle maintenance, longer timeline, larger portfolio required.
Two additional variants are worth exploring: Coast FIRE — where you've saved enough that compound growth will reach your FIRE number without additional contributions — and Barista FIRE, where part-time work covers basic expenses while investments grow. These hybrid models are increasingly popular for balancing early freedom with lower financial pressure.
FIRE calculators model averages — real retirement outcomes involve variability. Key risks to plan around:
Sequence of Returns Risk: Early retirement market crashes are far more damaging than late-career crashes. The portfolio has less time to recover before withdrawals begin eroding the base. Mitigation: 3–3.5% withdrawal rate, 1–2 year cash buffer, or part-time work flexibility.
Inflation Risk: The 4% Rule uses historical real returns — but 2–4% inflation meaningfully erodes purchasing power over 40-year retirements. The default 7% return in this calculator is already inflation-adjusted, which is why the 4% withdrawal rule applies directly.
Healthcare Costs: Pre-Medicare years (before age 65) require private health insurance. Budget $500–$1,500+/month per household depending on ACA subsidies, age, and location. This is often the largest FIRE budget surprise.
Lifestyle Inflation: Retirement spending often increases in the early years (travel, hobbies, home projects) before declining in later years. Modeling a "smile" spending curve rather than flat expenses can improve projection accuracy.