What you expect to spend per year
~7% is a common long-run stock estimate; use a lower real return for inflation-adjusted
25.0× annual expenses
FIRE — Financial Independence, Retire Early — is reached when your invested assets are large enough that a safe withdrawal covers your living costs forever. This calculator finds that target (your 'FIRE number') and projects how long it takes to get there.
Enter your annual spending, what you've already invested, how much you add each month, your expected return, and a withdrawal rate. It shows your FIRE number, years to independence, and Lean/Fat FIRE variants so you can see how lifestyle choices move the finish line.
FIRE Number = Annual Expenses ÷ (Withdrawal Rate ÷ 100)At a 4% withdrawal rate this equals 25× your annual spending. The portfolio is then grown month by month until it reaches that number.
Example: $50,000 spending, 4% rule
$50,000 ÷ 0.04 = FIRE number. Start with $80,000 invested, add $2,000/month at a 7% return.
FIRE number = $1,250,000 (25× expenses). Reaching it takes roughly 19-20 years given the contributions and growth.
Example: a more conservative 3.5% rate
Same spending but withdrawing 3.5% instead of 4%.
FIRE number rises to about $1,428,000 (≈28.5× expenses), adding a few years — the price of a bigger safety margin.
Methodology
FIRE number = annual expenses ÷ (withdrawal rate ÷ 100), i.e. 25× expenses at 4%. The portfolio is projected forward monthly at your expected return plus contributions until it crosses the FIRE number. Returns are nominal; for an inflation-adjusted view, enter a real (after-inflation) return.
The portfolio size where a safe withdrawal rate covers your spending. At 4%, that's 25× annual expenses — $40,000 of spending needs $1,000,000. A 3.5% rate (≈28.5×) is more conservative.
Based on the Trinity Study: withdraw 4% the first year, adjust for inflation after, with high odds the money lasts 30+ years. It's a guideline, not a guarantee — sequence risk and long retirements may justify a lower rate.
Lean FIRE = frugal budget and a smaller portfolio; regular FIRE = typical middle-class spending; Fat FIRE = higher spending and a much bigger portfolio. Same 4% math, different expense figure.
It's the biggest lever — saving 50% of income can reach FI in ~15-17 years, while 15% can take 40+. A higher savings rate grows the portfolio faster and lowers the expenses you must cover.
Disclaimer: Calculations are for informational purposes only and do not constitute professional financial advice. Please consult with a certified professional before making financial decisions.