What is FIRE?
FIRE = save enough so investments generate passive income to cover expenses. Your FIRE number = Annual Expenses ÷ Safe Withdrawal Rate.
The 4% Rule
The Trinity Study found 4% annual withdrawal gives 95%+ success over 30 years. FIRE number = 25 × Annual Expenses.
FIRE Variations
| Type | Description |
|---|---|
| Lean FIRE | <$40k/yr expenses |
| Regular FIRE | $40-80k/yr |
| Fat FIRE | $80k+/yr |
| Barista FIRE | Part-time work covers some expenses |
How to Use This FIRE Calculator
Enter your annual expenses, current savings, annual income, savings rate, and expected investment return. The calculator estimates your FIRE number and years to financial independence.
Formula & How It Works
FIRE Number = Annual Expenses Γ 25 (based on the 4% withdrawal rule). Years to FIRE β ln[(FI Number Γ r + Savings Rate) / (Current Savings Γ r + Savings Rate)] / ln(1 + r).
Calculation Example
Annual expenses $40,000: FIRE number = $1,000,000. Starting with $100,000 saved, adding $30,000/year at 7% returns: approximately 15 years to reach FIRE.
Expert Tips
Reducing expenses has a double effect β it lowers your FIRE number AND increases your savings rate. A 50% savings rate dramatically accelerates your timeline compared to 20%.
Frequently Asked Questions
Is the 4% rule still valid?
Some planners recommend 3.5% for 40+ year retirements. The original Trinity Study supported 30-year retirements.
What savings rate for FIRE?
50%+ is the target. At 50%, retire in ~17 years. At 70%, ~8.5 years.
Healthcare before Medicare?
Options: ACA marketplace plans, COBRA, health sharing ministries, or part-time work with benefits.