FIRE Calculator — Financial Independence Retire Early
Calculate your FIRE number — the portfolio size needed to retire early using the 4% rule. Estimate years to reach financial independence based on savings rate and expected returns.
How to Calculate Your FIRE Number
The foundation of FIRE is the 4% rule: a portfolio 25× your annual expenses can sustain indefinitely with a 4% annual withdrawal rate, based on historical market data (Trinity Study). Your "FIRE number" is simply your annual expenses × 25. The retirement planner calculator can project when you'll reach this target given your current savings and monthly contribution.
- FIRE number formula: Annual expenses × 25 = target portfolio size
- Example: $50,000/year expenses × 25 = $1,250,000 FIRE number
- Lean FIRE: Target under $1M — requires under ~$40,000/year spending
- Regular FIRE: $1M–$2.5M target — moderate lifestyle in most US cities
- Fat FIRE: $2.5M+ target — maintains high spending level (over $100K/year)
- Savings rate matters most: A 50% savings rate reaches FIRE in ~17 years vs 43 years at 10%
Choose the Right Variant
- This page: FIRE calculator — 4% rule, FIRE number, years to FI
- Retirement Planner: Full retirement projection tool
- Early Retirement Calculator: Plan for retiring before 60
- Investment Calculators: Project investment growth over time
Years to FIRE by Savings Rate
- 10% savings rate: ~43 years to FIRE
- 20% savings rate: ~37 years to FIRE
- 30% savings rate: ~28 years to FIRE
- 40% savings rate: ~22 years to FIRE
- 50% savings rate: ~17 years to FIRE
- 60% savings rate: ~12 years to FIRE
- 75% savings rate: ~7 years to FIRE
- Assumes 7% real return (inflation-adjusted), spending from non-savings income
Privacy and Data Handling
All calculations run locally in your browser. Your financial data is never sent to any server and is not stored.
Frequently Asked Questions
What is the 4% rule and is it still valid?
The 4% rule (Bengen Rule) states that withdrawing 4% of your portfolio in year 1, adjusted for inflation each year after, has historically sustained a 30-year retirement across all historical US market periods (including the Great Depression and 1970s stagflation). For FIRE purposes, the concern is that many FIRE retirees need 40–60 year portfolios, not 30 years. Research suggests 3.5% is safer for 40-year periods; 3.25% for 50+ years. Many FIRE practitioners use 3.5% as their withdrawal rate (meaning 28.6× expenses as the target) for more conservatism.
How do I calculate my FIRE number if my expenses will change in retirement?
Use your projected retirement expenses, not your current expenses. Budget for: (1) no more mortgage if you'll pay it off, (2) healthcare costs (likely higher without employer coverage — budget $600–$1,200/month per person before Medicare), (3) lower commuting/work clothing/childcare costs, (4) potentially higher travel and leisure spending. If your retirement expenses are significantly different from today's, recalculate: lower expenses reduce the FIRE number substantially, while adding healthcare can increase it by $200,000–$400,000.
Should I include Social Security in my FIRE calculations?
This depends on your FIRE age. If you plan to retire in your 30s or 40s, Social Security is 25–30 years away — don't rely on it for near-term planning. However, it's reasonable to model it as a supplemental income source that reduces required portfolio withdrawals starting at 62–70. Each $1,000/month in Social Security income reduces your required FIRE number by approximately $300,000 (at 4% withdrawal rate). Use a conservative estimate (50–75% of projected benefits to account for potential future benefit changes) in your long-range models.