The 4% rule is the most cited guideline in retirement planning. Developed by financial planner William Bengen in 1994, it provides a simple framework for how much you can safely withdraw from your retirement savings each year.
How the 4% Rule Works
- Year 1: Withdraw 4% of your total portfolio value
- Subsequent years: Adjust the withdrawal by the inflation rate
- Result: In Bengen’s historical tests, the money lasted at least 30 years
The Math: How Much You Need
The inverse of the 4% rule gives you the “multiply by 25” rule — multiply your desired annual spending by 25 to find your target nest egg:
| Desired Annual Spending | Portfolio Needed (25x) | Monthly Withdrawal |
|---|---|---|
| $30,000 | $750,000 | $2,500 |
| $40,000 | $1,000,000 | $3,333 |
| $50,000 | $1,250,000 | $4,167 |
| $60,000 | $1,500,000 | $5,000 |
| $80,000 | $2,000,000 | $6,667 |
| $100,000 | $2,500,000 | $8,333 |
| $150,000 | $3,750,000 | $12,500 |
Example: $1.2 Million Portfolio
| Year | Withdrawal | Inflation Adj. | Remaining Portfolio* |
|---|---|---|---|
| 1 | $48,000 (4%) | — | $1,152,000 |
| 5 | $52,500 | 3%/year | $1,189,000 |
| 10 | $60,800 | 3%/year | $1,195,000 |
| 15 | $70,500 | 3%/year | $1,140,000 |
| 20 | $81,700 | 3%/year | $1,008,000 |
| 25 | $94,700 | 3%/year | $782,000 |
| 30 | $109,800 | 3%/year | $438,000 |
*Assumes 7% nominal return on a 60/40 portfolio.
Historical Success Rate
Bengen’s 1994 research tested the 4% rule against historical U.S. market data, using a portfolio of 50% intermediate-term Treasury notes and 50% common stocks. His finding: a first-year withdrawal of 4%, followed by inflation-adjusted withdrawals, should be safe for a minimum of 30 years, and in no past case did it exhaust a portfolio before 33 years.
The Trinity Study (Cooley, Hubbard and Walz) later tested a range of withdrawal rates and stock/bond mixes over payout periods of up to 30 years, and its authors concluded that portfolios of at least 75% stock supported inflation-adjusted withdrawals of 4% to 5%. Past results do not guarantee future ones, and the exact odds depend on the period tested, the asset mix and the withdrawal rate.
Limitations of the 4% Rule
1. Based on U.S. Historical Data
The 4% rule uses U.S. stock and bond returns from 1926 onward. Future returns may be lower, particularly if current valuations and interest rates don’t revert to historical norms.
2. Fixed Spending Is Unrealistic
Most retirees don’t spend the same inflation-adjusted amount every year. Spending typically follows a “smile” pattern — higher in early retirement (travel, activities), lower in mid-retirement, and higher again in late retirement (healthcare).
3. 30-Year Horizon May Not Be Enough
For early retirees or those retiring at 60, a 30-year horizon may be insufficient. A 40-year horizon suggests a 3.3-3.5% rate.
4. Ignores Taxes
The 4% rule doesn’t account for the tax impact of withdrawals. $40,000 from a Traditional IRA is worth less than $40,000 from a Roth IRA.
5. Sequence of Returns Risk
Poor market returns in the first few years of retirement can devastate a portfolio even if long-term averages are fine. This “sequence risk” is the biggest threat to the 4% rule’s success.
Modern Alternatives to the 4% Rule
The 3.3% Rule (More Conservative)
Researchers like Wade Pfau suggest 3.3% may be more appropriate given current market conditions, especially for early retirees or those prioritizing safety.
The Guardrails Method
Set upper and lower spending boundaries:
- If your portfolio grows significantly, increase withdrawals (up to a cap)
- If your portfolio declines below a threshold, temporarily reduce withdrawals
Dynamic Spending
Adjust withdrawals each year based on portfolio performance rather than a fixed percentage. Spend more after good years, less after bad years.
The Bucket Strategy
Divide your portfolio into buckets:
- Bucket 1 (1-2 years): Cash and short-term bonds for immediate spending
- Bucket 2 (3-7 years): Bonds and moderate-risk investments
- Bucket 3 (8+ years): Stocks for long-term growth
Refill Bucket 1 from Bucket 2, and Bucket 2 from Bucket 3 as markets allow.
Adjusting for Early Retirement
If you retire before 65, the 4% rule may need modification:
| Retirement Age | Years Until ~90 | Suggested Rate |
|---|---|---|
| 65 | 25 | 4.0% |
| 60 | 30 | 3.7% |
| 55 | 35 | 3.5% |
| 50 | 40 | 3.3% |
| 45 | 45 | 3.0% |
FIRE (Financial Independence, Retire Early) adherents often plan for 3.0-3.5% withdrawal rates to account for longer time horizons.
The 4% Rule With Social Security
For most retirees, Social Security covers a portion of expenses, meaning the 4% rule only needs to cover the gap:
| Annual Spending | Social Security | Withdrawal Needed | Portfolio Needed |
|---|---|---|---|
| $50,000 | $24,000 | $26,000 | $650,000 |
| $70,000 | $24,000 | $46,000 | $1,150,000 |
| $70,000 | $40,000 (couple) | $30,000 | $750,000 |
| $100,000 | $40,000 (couple) | $60,000 | $1,500,000 |
Social Security dramatically reduces the portfolio needed, especially for moderate spenders.
For more on FIRE strategies and numbers, see the FIRE hub.
For more on FIRE strategies and numbers, see the FIRE hub.
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