How much do I need to retire early?

What is a FIRE number?

FIRE stands for Financial Independence, Retire Early. Your FIRE number is the size of invested portfolio that could fund your lifestyle indefinitely from investment returns alone. The math behind it is simple:

• FIRE number = annual spending ÷ safe withdrawal rate

At a 4% withdrawal rate, that's just spending × 25. Spend $60,000 a year and your FIRE number is $1.5 million. Choose a more conservative 3.33% rate and it climbs to spending × 30 ($1.8 million) — the lower the rate you trust, the bigger the cushion you need.

Where the 4% rule comes from

The 4% "safe withdrawal rate" comes from the Trinity study and William Bengen's research, which tested historical 30-year retirements and found that withdrawing 4% of the starting portfolio (then adjusting for inflation each year) rarely ran out of money. It's a rule of thumb, not a law — a longer early retirement, a weak first decade of returns, or high fees can all argue for a lower rate. This calculator lets you dial the rate between 2.5% and 5% so you can see the effect on your target.

Lean FIRE, regular FIRE, and Fat FIRE

People aim at different versions of FIRE depending on the lifestyle they want to fund:

• Lean FIRE — a frugal early retirement, often spending under ~$40,000 a year, so the FIRE number is smaller (roughly $1 million or less at 4%). It reaches independence sooner but leaves little slack.
• Regular / traditional FIRE — a middle-class lifestyle, typically $40,000–$100,000 of annual spending, targeting roughly $1M–$2.5M.
• Fat FIRE — a comfortable, no-compromises retirement, usually $100,000+ of spending and a FIRE number well north of $2.5 million.
• Coast FIRE — you've invested enough that, without adding another dollar, growth alone will reach your FIRE number by traditional retirement age; you only need to cover current expenses until then.

Methodology

This tool works entirely in today's dollars. By asking for a real (after-inflation) return, every figure — your FIRE number, projected portfolio, and the balances in the chart — is already inflation-adjusted, so you can compare them directly to what money buys now. Each month we grow your balance by the monthly-equivalent of your real return and add your contribution, then check whether the balance has crossed your FIRE number. The "age you reach FIRE" is the first month the portfolio meets or exceeds the target.

Honest caveats

• Sequence-of-returns risk. A steady average return hides the real danger: a bad run of returns in your first few retirement years can sink a portfolio even if the long-run average is fine. Retiring early stretches your horizon and magnifies this risk — many early retirees use a lower withdrawal rate or a cash buffer as insurance.
• Everything is in today's dollars. We assume a real return and level real spending. If you enter a nominal return by mistake, the projection will look far too optimistic.
• No taxes or healthcare. Withdrawals from pre-tax accounts are taxable, and health insurance before Medicare can be a large early-retirement expense. Your true spending target may be higher than headline spending.
• Contributions and spending are held flat. Real life includes raises, career breaks, and lifestyle changes this simple model doesn't capture.

Frequently asked questions