How to Calculate Your FIRE Number
Learn the simple FIRE number formula, when 25x expenses is too aggressive, and how to choose a safer withdrawal-rate target.
Your FIRE number is the portfolio size that can support your annual expenses without salary income. The math is simple, but the assumptions behind it decide whether the plan is resilient or fragile.
FIRE Number = Annual Expenses ÷ Safe Withdrawal Rate
At 4%, this becomes Annual Expenses × 25.
Run your spending and withdrawal-rate assumptions through the dedicated FIRE number calculator.
Calculate Your FIRE Number →Start with spending, not income
FIRE is controlled by expenses. If you spend $60,000 per year, a 4% withdrawal rate implies a $1.5M target. At 3.33%, the same lifestyle needs about $1.8M. A higher salary helps you reach the target faster, but it does not reduce the target unless your spending falls.
When 25x is not enough
The 25x rule assumes a 4% withdrawal rate. That may be reasonable for a traditional 30-year retirement, but early retirees often need a longer runway. If your retirement could last 45-55 years, use 28x-33x as a conservative planning range.
Use three scenarios
- Base: current annual expenses × 25.
- Safer: current annual expenses × 30.
- Stress case: future expenses after healthcare, housing, and tax changes × 33.
The practical test
Next steps
After estimating the target, use the full Financial Independence Retire Early Calculator to test your timeline, then compare Coast and Barista FIRE if full early retirement feels too far away.
Key Takeaways
- Your FIRE number is annual expenses divided by withdrawal rate.
- 25x expenses is a starting point, not a guarantee.
- Long early retirements usually need a 28x-33x range.
- Reducing spending helps twice: it raises savings and lowers the required portfolio.