FIRE: Retirement Calculator app iconFIRE

What's my FIRE number?

Your FIRE number is the amount you need invested to live off your portfolio. Here's the formula, an example, and a calculator.

The formula

Your FIRE number is your annual retirement expenses divided by your safe withdrawal rate. At the common 4% rule, that is your yearly spending times 25. If you expect to spend $50,000 a year, your FIRE number is about $1,250,000 ($50,000 ÷ 0.04).

It is the portfolio size that can fund your spending indefinitely, because a sustainable withdrawal rate lets the remaining balance keep growing to cover future years and inflation.

Plan in today's dollars

Enter spending in today's dollars and use a real (after-inflation) return — historically around 7% nominal minus roughly 3% inflation, so about a 4% real growth assumption for a stock-heavy portfolio. That keeps your FIRE number meaningful decades out without guessing future price levels.

Your spending figure should include the taxes you'll owe on withdrawals — the 4% rule assumes the withdrawal covers your total outflow, not just take-home spending.

How many years until you reach it

Once you know the number, the question becomes when. That depends on what you have invested now, how much you add each year, and your expected real return. The calculator below solves for the crossover year — and the app turns that date into a live home-screen countdown that moves closer as you invest.

FIRE calculator

Runs in your browser — nothing is sent anywhere.

This calculator gives educational estimates only. It plans in today's dollars using a real (after-inflation) return, so your FIRE number reflects total spending including any taxes you'll owe. Projections are illustrative, not guarantees, and this is not financial advice.

Questions

What is the FIRE number formula?

FIRE number = annual retirement expenses ÷ safe withdrawal rate. At a 4% withdrawal rate that equals your yearly spending × 25.

Is the FIRE number 25 times expenses?

Only at a 4% safe withdrawal rate. At 3.5% it's about 28.5× expenses; at 5% it's 20×. The multiple is 1 divided by your withdrawal rate.

Should my expenses include taxes?

Yes. The 4% rule assumes the withdrawal covers your total spending, including any income tax owed on withdrawals, so enter a tax-inclusive number.

Related guides

Find your date, then count down to it

See your number free above, then put the countdown on your iPhone home screen.