FIRE Retirement Calculator
Calculate your FIRE number, savings rate, and projected retirement age. Instantly see years to financial independence using the 4% rule and compound growth.
How It Works
FIRE number = annual expenses × 25 (based on the 4% withdrawal rule). Savings rate and investment returns determine years until your portfolio reaches that target.
Formula
FIRE Number = Annual Expenses × 25
Years to FIRE = ln((FIRE Number × (r - g) / Savings) + 1) / ln(1 + (r - g))
The formula uses future value of an annuity. r = investment return rate, g = inflation rate. It calculates the time needed for your current investments + monthly savings to reach the FIRE number.
Worked Example
Reaching FIRE with $40,000 Annual Expenses
- Annual Expenses: $40,000
- FIRE Target: $40,000 × 25 = $1,000,000
- Current Savings: $100,000
- Monthly Contribution: $2,000
- Assumed Return: 7% after inflation
- Time to reach $1,000,000: Approximately 15 years.
Common Mistakes
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Ignoring inflation
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Always use an inflation-adjusted return (e.g., 7% instead of 10%) so your FIRE number retains its purchasing power.
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Underestimating healthcare costs
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Remember that early retirement means you must pay out-of-pocket for health insurance until Medicare kicks in.
Frequently Asked Questions
Related Guide & Instructions
2026-07-10
The Beginner's Guide to FIRE: How to Calculate Your Financial Independence Number
Learn what the FIRE movement is, how to calculate your retirement target using the 4% rule, and explore Coast FIRE.
Read full guide →Related Calculators
DisclaimerThe results provided by this calculator are estimates and for informational purposes only. They do not constitute financial, legal, or professional advice. Please consult with a qualified professional for your specific needs.