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

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

What is the 4% rule, exactly?

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 Trinity Study, a 1998 analysis by three finance professors who examined every 30-year period between 1926 and 1995 using historical stock and bond return data.

The study found that a 50/50 stock-bond portfolio survived a 30-year draw-down in nearly every historical scenario when withdrawals were capped at 4% of the initial portfolio value, adjusted upward each year with inflation.

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.

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:

1. Estimate your annual retirement spending. Include housing, food, healthcare, travel, and discretionary expenses. Be honest — underestimating is the most common retirement planning mistake.
2. 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.
3. Multiply the gap by 25. This is your target portfolio number under the 4% rule.
4. 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.

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.