A real example: the 25× rule in action
Say you can live comfortably on $40,000 a year. The 4% rule says you can retire once you've saved about 25 times your annual spending:
$40,000 × 25 = $1,000,000 — that's your FIRE number, the point where a 4% withdrawal ($40,000) covers your life indefinitely.
How fast you get there depends almost entirely on your savings rate. Starting from zero and investing at a 7% return, saving 50% of a $60,000 income reaches $1M in roughly 18 years; saving 25% takes closer to 26 years. Enter your spending and savings above to find your own timeline.
How the FIRE number is calculated
Your FIRE number is the size of investment portfolio that can fund your lifestyle indefinitely. It comes from the safe withdrawal rate:
FIRE number = Annual spending ÷ Safe withdrawal rate
At a 4% withdrawal rate, that's simply your annual spending × 25. So if you spend $40,000 a year, you'd aim for a $1,000,000 portfolio. The idea, based on the well-known Trinity Study, is that a diversified portfolio can sustain roughly 4% annual withdrawals (adjusted for inflation) over a long retirement.
For the full walkthrough — the three-step calculation, the four adjustments most people miss (mortgage, healthcare, taxes, inflation) and what actually moves the date — read what's your financial freedom number?
The three levers of early retirement
- Spend less: lower spending shrinks your FIRE number and raises your savings rate — a double win.
- Save more: your savings rate is the biggest driver of how soon you reach FI.
- Invest wisely: consistent, low-cost investing lets compounding accelerate your timeline.
Tools to get there faster
Low-cost investing
Most of the FIRE community builds wealth with broad, low-fee index funds.
Compare brokers →Net-worth tracking
Seeing your savings rate and net worth in one place keeps you on plan.
See tools →Frequently asked questions
Is the 4% rule safe?
It's a strong rule of thumb for a ~30-year retirement, but early retirees with 40–50 year horizons often use a more conservative 3.25–3.5%. Lower the withdrawal rate for a bigger safety margin.
Does this include inflation?
Use a "real" (after-inflation) return — around 7% historically becomes ~5% real. The withdrawal rate already assumes inflation-adjusted spending.
What about Social Security or a pension?
This calculator focuses on portfolio-funded independence. Future guaranteed income would reduce the portfolio you need.