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你的 FIRE 数字——精简、常规或丰厚

4% 法则说，当你的投资储蓄达到约年支出的 25 倍时即可退休。这是你的数字、你所处的位置，以及距离自由还有多少年。

Last updated: June 2026

Your FIRE number (Financial Independence, Retire Early) is the size of invested portfolio that can fund your lifestyle indefinitely without a paycheck. The standard shortcut is the 4% rule: withdraw 4% of your portfolio in year one, adjust that dollar amount for inflation every year after, and historically that has lasted at least 30 years across most rolling periods in US market history. Flipping the percentage into a multiple gives the "25x rule" — annual spending × 25 — because 1 ÷ 0.04 = 25.

Where the 4% rule comes from

The figure traces to William Bengen's 1994 research and the later Trinity study (Cooley, Hubbard & Walz, 1998), which tested fixed withdrawal rates against historical US stock/bond returns for 30-year retirements. A 4% starting withdrawal, rebalanced across a 50/50 to 75/25 stock/bond mix, survived nearly all historical 30-year windows. It was never a guarantee — it's a backtest over one country's market history.

A worked example

Say your household spends $48,000 a year in retirement. At a 4% withdrawal rate, your FIRE number is $48,000 × 25 = $1,200,000. Want more of a margin of safety? Use 3.5% instead (multiple of ~28.6), pushing the target to roughly $1,373,000 — the trade-off between a bigger cushion and working longer to get there.

Why the multiple isn't fixed

Retiring at 35 with a 55-year time horizon carries more sequence-of-returns risk than retiring at 65 with a 25-year one, so long early-retirement horizons often justify a lower withdrawal rate (3% to 3.5%) rather than the traditional 4%. Fee drag, non-US market exposure, and flexible spending (cutting back in down years) all shift the safe number too.

Common pitfalls

People often forget to inflation-adjust their spending estimate, ignore healthcare costs before Medicare/national-health eligibility ages, and treat 4% as risk-free rather than "held up in most historical scenarios." Taxes on withdrawals, one-off costs (a new roof, a wedding), and the fact that US historical returns may not repeat are all reasons planners increasingly favor 3.25%-3.75% for anyone retiring before their mid-60s.

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参考：在你的提取率下，各种生活方式所需的金额
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4% 法则是源自美国历史数据的实用经验法则，并非保证——回报序列风险真实存在。属于教育，而非建议。 计算方法.

Frequently asked questions

What is a FIRE number?
Your FIRE number is the amount of invested savings that lets you live off withdrawals indefinitely. The classic estimate is your annual expenses × 25 — the inverse of the 4% safe-withdrawal rule.
How do I calculate my FIRE number?
Multiply your expected annual spending in retirement by 25 (for a 4% withdrawal rate). For example, $40,000 a year × 25 = a $1,000,000 FIRE number. A more conservative 3.5% rule uses ×28.5.
What's the difference between Lean, Regular and Fat FIRE?
Lean FIRE covers a frugal lifestyle (often under ~$40k/year), Regular FIRE a typical middle-class one, and Fat FIRE a comfortable, higher-spending one. Each just changes the annual-expenses figure you multiply by 25 — see the types of FIRE guide.
Is the 4% rule safe?
It comes from the Trinity study and held up across most historical 30-year periods, but it's a guideline, not a guarantee. Sequence-of-returns risk and low-return decades can stress it, so many early retirees use 3.25–3.5%. Check how long a pot lasts with the drawdown calculator.
Where does the 4% rule actually come from?
It traces to William Bengen's 1994 research and the later Trinity study. For the full history, every FIRE variant with worked math, and the healthcare bridge, see the complete guide to FIRE.