How to calculate fire
FIRE number = Annual spending ÷ Withdrawal rate
Worked example. Your FIRE number: $1,250,000.
Example inputs — Annual spending in retirement: $50,000; Current savings: $100,000; Annual savings contribution: $30,000; Expected annual return: 7%; Safe withdrawal rate: 4%. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Your FIRE number is the portfolio size where a safe withdrawal rate (commonly 4%) covers your annual spending forever. We grow your current savings plus contributions at your expected return until you hit it.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
Why 4%?
The '4% rule' comes from the Trinity Study: historically, withdrawing 4% of a balanced portfolio yearly lasted 30+ years.
Should I include my house?
Only include assets that produce income or can be sold to fund spending.