What Is the 4% Rule? The Safe Withdrawal Rate Explained

Q: Does the 4% rule account for inflation?

Yes. The original Trinity Study used inflation-adjusted withdrawals. You start with 4% of your portfolio, then increase the dollar amount by CPI each year. The 4% is the first-year withdrawal rate, not a fixed dollar amount.

Q: What happens if markets crash right after I retire?

This is sequence-of-returns risk — the biggest threat to the 4% rule. Selling shares at depressed prices early in retirement locks in permanent losses. Mitigation strategies include a cash buffer, a bond tent, or a flexible spending rule.

Q: Should I use the 4% rule or 3.5% rule?

Use 4% (25× expenses) if retiring at 65+ with a 30-year horizon. Use 3.5% (28.5× expenses) if retiring early or in a high-valuation environment. The more conservative rate provides a cushion against extended low-return periods.

The 4% rule says you can withdraw 4% of your retirement portfolio each year without running out of money over 30 years. Here is where it came from, how to calculate it, and when to use 3.5% instead.

The 4% rule says you can withdraw 4% of your retirement portfolio each year without running out of money over a 30-year retirement. A $1,000,000 portfolio supports $40,000 per year; a $1,500,000 portfolio supports $60,000. It is the most widely used shorthand for deciding when you have enough saved to retire.

What is the 4 percent rule

The 4% rule is a safe withdrawal rate — the maximum percentage of a retirement portfolio you can withdraw each year, adjusted for inflation, while maintaining a high probability that the money lasts 30 years or more. It was derived from the 1998 Trinity Study.

Withdrawal rate: withdraw 4% of your initial portfolio balance in year one, then increase that dollar amount each year with inflation.
Portfolio size (25× rule): multiply your annual retirement expenses by 25 to find the portfolio needed — because 1 ÷ 0.04 = 25.
Historical success rate: a 50/50 stock-bond portfolio survived every 30-year period in 95% of historical scenarios tested from 1926 to 1995.

How do you calculate the 4% rule?

The calculation works in both directions depending on what you are solving for:

How much can I withdraw? Multiply your portfolio by 0.04. A $1,500,000 portfolio supports $60,000/year in withdrawals.
How much do I need to retire? Divide your annual expenses by 0.04 — or equivalently, multiply by 25. Spending $50,000/year requires a $1,250,000 portfolio. This is the 25× rule.

Annual spending	Portfolio needed (25×)	Annual 4% withdrawal
$30,000	$750,000	$30,000
$50,000	$1,250,000	$50,000
$70,000	$1,750,000	$70,000
$100,000	$2,500,000	$100,000

Use the 4% Rule Calculator to enter your specific portfolio and spending figures and see whether you can retire today under the safe withdrawal rate.

Where did the 4% rule come from?

The rule originated in a 1998 paper titled "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable" by Cooley, Hubbard, and Walz — three finance professors at Trinity University in San Antonio, Texas. The paper became widely known as the Trinity Study.

Their methodology: test every 30-year withdrawal scenario from 1926 to 1995 across different portfolio allocations (100% stocks, 75/25, 50/50, 25/75, 100% bonds) and different withdrawal rates (3%, 4%, 5%, 6%, 7%, 8%). The key metric was "portfolio success rate" — the percentage of historical periods where the portfolio survived the full 30 years without hitting zero.

A 50/50 stock-bond portfolio with a 4% withdrawal rate succeeded in 95% of all historical 30-year periods. A 100% stock portfolio at 4% succeeded in 98%. At 5%, success rates dropped to 80% — too many failure scenarios. At 3%, success was near-universal but left most retirees with far more money than needed at death. 4% became the consensus "sweet spot."

Is the 4% rule still valid today?

The 4% rule remains the most widely cited retirement benchmark, but several researchers have updated the analysis for current conditions:

Morningstar (2023) suggested 3.8% as a more conservative starting withdrawal rate given lower expected bond returns in the current interest rate environment.
Vanguard (2023) estimated a 3.3% withdrawal rate for a 90% success probability over 30 years with a balanced portfolio.
Early retirees (40–50+ year retirements) should use 3.5% or lower — the Trinity Study was designed for exactly 30 years. Longer draw-down periods introduce more sequence-of-returns risk.

The original 4% rule is still a reliable starting point for planning purposes. Use it to estimate your retirement number, then stress-test with a financial planner for your specific situation and timeline.

What are the criticisms of the 4% rule?

Several limitations are worth understanding before relying on the 4% rule:

It assumes a fixed withdrawal amount. Real retirees adjust spending based on market conditions. Spending 4% in a crash year when the portfolio has fallen 40% accelerates depletion.
It does not account for taxes. Withdrawals from a Traditional 401k or IRA are taxed as ordinary income. Your actual spendable amount is lower than the 4% figure.
It ignores Social Security and pensions. If you have guaranteed income from Social Security or a pension, your portfolio needs to cover only the gap — not your full expenses. This can significantly reduce your required savings.
It was designed for US markets. Historical US returns were unusually strong. International retirees or those expecting lower growth should use a more conservative rate.

How do I use the 4% rule to plan my retirement?

A practical four-step process:

Estimate your annual retirement spending. Include housing, food, healthcare, travel, and discretionary expenses. Be honest — underestimating is the most common retirement planning mistake.
Subtract guaranteed income. Deduct Social Security, pension payments, or rental income from your annual spending estimate. The 4% rule only needs to cover the remaining gap.
Multiply the gap by 25. This is your target portfolio number under the 4% rule.
Adjust for your retirement timeline. If retiring before 65, multiply by 28.5 (3.5% SWR) instead of 25. If retiring at 70+, 25 or even slightly above may be appropriate.

For a complete walkthrough including Social Security offsets, age-based adjustments, and how to build toward your number, see our guide on how much you need to retire. The 4% rule is one component of a full retirement calculation — not the complete picture on its own.

To model how your 401k and Roth IRA contributions will grow toward the retirement number the 4% rule defines, see our guide on choosing between a Roth IRA and a 401k.

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Key takeaways

The 4% rule: withdraw 4% of your retirement portfolio each year, adjusted for inflation, to sustain a 30-year retirement.
Your retirement number = annual expenses × 25 (the 25× rule — the inverse of 4%).
The rule comes from the 1998 Trinity Study analysing historical US portfolio performance from 1926–1995.
For retirements of 35–40+ years (early retirement), use a 3.5% withdrawal rate (28.5× expenses) instead.
The 4% rule does not account for taxes, flexible spending, or Social Security — use it as a starting estimate, not a precise guarantee.

Frequently asked questions

What is the difference between the 4% rule and the 25x rule?

They are the same concept expressed differently. The 4% rule describes the annual withdrawal rate. The 25× rule describes the portfolio size needed — because 1 ÷ 0.04 = 25. If you need $60,000/year, you need $1,500,000 saved (25× $60,000). Withdrawing $60,000 from $1,500,000 is exactly 4%.

Does the 4% rule account for inflation?

Yes — the original Trinity Study used inflation-adjusted withdrawals. You start by withdrawing 4% of your initial portfolio, then increase the dollar amount each year with CPI. So if you start withdrawing $40,000/year and inflation is 3%, you withdraw $41,200 the next year, then $42,436 the year after, and so on. The portfolio must sustain this growing withdrawal stream for 30 years.

Can I use the 4% rule if I have a pension or Social Security?

Yes — and guaranteed income makes the 4% rule much more achievable. If your spending is $60,000/year and Social Security covers $24,000, your portfolio only needs to provide $36,000/year. Your required portfolio is $36,000 × 25 = $900,000 — not $1,500,000. Every dollar of guaranteed income reduces your required savings by $25.

What happens if markets crash right after I retire?

This is called sequence-of-returns risk — the biggest threat to the 4% rule in practice. Withdrawing 4% when your portfolio has fallen 40% forces you to sell depressed assets, reducing future recovery. Common mitigations: keep 1–2 years of expenses in cash, reduce withdrawals in down years, or use a dynamic withdrawal strategy (withdraw less when the portfolio falls below a threshold).

Should I use the 4% rule or 3.5% rule?

Use 4% (25× expenses) if you plan to retire at or after 65 with a 30-year horizon. Use 3.5% (28.5× expenses) if retiring before 60 with a 35–40+ year horizon. Use 3% (33× expenses) for very early retirement or if you want extremely high historical success rates in conservative market scenarios.