What Is the 4 Percent Rule and Does It Still Work Given Current Inflation

What Is the 4 Percent Rule and Does It Still Work Given Current Inflation

This article is for informational purposes only and does not constitute financial advice. Every person's financial situation is unique. Please consult a qualified financial advisor before making any retirement planning decisions.

Picture this. You have spent thirty years building a retirement nest egg. You have watched it grow through bull markets, shrink through crashes, and slowly recover again. Now you are standing at the edge of retirement, calculator in hand, asking the question that keeps every soon-to-be retiree awake at night. How much can I actually spend each year without running out of money before I run out of years?

For decades, one answer has dominated the conversation. Four percent. Withdraw four percent of your portfolio in your first year of retirement, adjust that amount upward each year for inflation, and history suggests your money will last at least thirty years. Simple. Elegant. Reassuring.

But we are not living in the world that created the four percent rule. Inflation has done things in the past few years that a generation of retirees never expected to see. Interest rates moved in ways that upended decades of conventional wisdom about balanced portfolios. And the people planning retirement today are living longer than the retirees whose data underpinned the original research. The four percent rule deserves a hard, honest look.

Where the Four Percent Rule Came From

In 1994, financial planner William Bengen published research that changed retirement planning permanently. He studied historical market data going back to 1926 and asked a specific question. What is the highest withdrawal rate that would have survived every thirty-year retirement period in that historical record, including the worst ones?

The answer was 4.15 percent, which Bengen rounded down to four percent for safety. His research included the Great Depression, the stagflation of the 1970s, the crashes of 1937 and 1973 to 1974. A retiree following the four percent rule with a portfolio split roughly between stocks and bonds would have survived every historical thirty-year period without running out of money.

This was not a guarantee about the future. It was a statement about the past. Bengen was clear about this distinction. The four percent rule meant that based on every historical scenario available, a four percent withdrawal rate had never failed over thirty years. It said nothing about scenarios that history had not yet produced.

What the Rule Actually Says and What It Does Not

Before examining whether the rule still works, it helps to understand exactly what it says.

The rule applies to the first year of retirement only. You take four percent of your total portfolio value on the day you retire. If you have $800,000, you withdraw $32,000 in year one — approximately $2,667 per month.

In every subsequent year you adjust that dollar amount upward by inflation, not four percent of your current portfolio value. This distinction matters enormously. If inflation runs at three percent in year two you withdraw $32,960 not a fresh four percent of whatever your portfolio is worth. If your portfolio dropped to $650,000 in year two you still take $32,960. The original dollar amount inflates forward regardless of market performance.

This inflation adjustment is what makes the rule both powerful and vulnerable. It protects your purchasing power in good times. It accelerates depletion in bad times when your portfolio has dropped but your withdrawal keeps climbing with inflation.

The rule also assumes a specific portfolio allocation — roughly fifty to seventy-five percent stocks and the remainder in bonds. It does not work the same way for a portfolio that is one hundred percent cash or one hundred percent stocks.

The Inflation Problem That Changes Everything

From 1994 when Bengen published his research through 2020, inflation in the United States averaged approximately 2.3 percent annually. Bengen's historical data included the brutal inflation of the 1970s but the thirty-year periods he studied averaged out to manageable inflation levels overall.

Then 2021 happened. Then 2022. The Consumer Price Index peaked at 9.1 percent in June 2022, a level not seen since 1981. Grocery prices surged. Utility bills climbed. Healthcare costs, which were already inflating faster than general CPI, accelerated further. Rent in major cities jumped 25 to 30 percent in two years. The cumulative price increase from 2020 through 2024 left most retirees spending significantly more dollars to maintain the same lifestyle than any pre-pandemic projection assumed.

The four percent rule's built-in inflation adjustment was supposed to handle this. But the rule assumes inflation averages out over time. A retiree who retired in 2020 and applied the four percent rule saw their withdrawal amount jump dramatically in 2022 and 2023 to keep pace with actual inflation. If their portfolio also declined during the 2022 market correction — when both stocks and bonds fell simultaneously, which the rule's historical data treated as rare — the combination of high inflation-adjusted withdrawals and a declining portfolio created a doubly difficult situation.

This is called sequence of returns risk. Getting hit with poor market performance in the early years of retirement while simultaneously needing to increase withdrawals to match inflation is mathematically the worst possible combination. The four percent rule historically survived this combination. But the 2022 scenario of simultaneous stock declines, bond declines, and high inflation was more extreme than anything in Bengen's original data set.

The Longevity Problem the Rule Did Not Anticipate

Bengen designed his research around thirty-year retirements. In 1994 that was a reasonable planning horizon for someone retiring at sixty-five. Average life expectancy suggested most people would not need their portfolio to last much beyond age ninety-five.

Today the picture is different. Advances in medicine, nutrition, and healthcare mean that a healthy sixty-two-year-old has a meaningful probability of living into their nineties. A couple retiring together at sixty-two faces a significant chance that one of them will live past ninety-five. Planning for a thirty-year retirement may leave a decade or more of life uncovered.

When researchers extended Bengen's analysis to forty-year retirements the safe withdrawal rate dropped. Depending on the historical period studied, a forty-year retirement requires something closer to three to three-and-a-half percent to achieve the same historical survival rate that four percent achieved over thirty years. For someone retiring at fifty-five with a potential forty-five-year retirement horizon the math becomes even more conservative.

The Interest Rate Complication

The four percent rule was built partly on the assumption that bonds provide meaningful income and stability within a retirement portfolio. When ten-year Treasury bonds yielded six to eight percent in the 1990s, the bond portion of a balanced portfolio generated significant income that reduced the need to sell assets to fund withdrawals.

The decade from 2010 to 2020 broke this assumption. Interest rates fell to near zero. Ten-year Treasury bonds yielded one to two percent for extended periods. The bond portion of a balanced retirement portfolio provided almost no income and offered limited protection against stock market declines. Retirees relying on the four percent rule during this period were drawing down principal far faster than historical models suggested.

Rates have since risen significantly. The Federal Reserve's aggressive rate increases from 2022 onward brought ten-year Treasury yields back above four percent for the first time in over a decade. For retirees who can hold bonds to maturity, the income picture improved substantially. But the decade of near-zero rates did real damage to many retirement portfolios that were built on the assumption of meaningful bond income.

The One-Size Problem

Perhaps the most significant limitation of the four percent rule is that it applies a single number to situations that vary enormously.

A retiree with substantial Social Security income, a defined benefit pension, and a paid-off home in a low-cost area has fundamentally different portfolio withdrawal needs than a renter in a high-cost city with no pension and Social Security as their only guaranteed income. The four percent rule treats both identically.

Spending in retirement is also not uniform across time. Most retirees spend more in their early active retirement years — travel, hobbies, family events — and less in their later years as activity levels naturally decline. Then healthcare costs surge in the final years, often dramatically. Applying a flat inflation-adjusted withdrawal to this naturally variable spending pattern is an imperfect fit.

Per-category inflation makes this even more important. Healthcare has inflated at five to seven percent annually for decades regardless of what general CPI does. A retiree who spends heavily on healthcare faces a personal inflation rate that is meaningfully higher than the general CPI number used in the standard four percent rule calculation. Their effective safe withdrawal rate is lower than the rule suggests because their personal cost of living is rising faster than average inflation.

So Does It Still Work

The honest answer is that the four percent rule remains a useful starting point but should not be treated as a reliable precision tool in the current environment.

For someone retiring at sixty-five with a thirty-year horizon, a traditional balanced portfolio, inflation that returns to two to three percent over the long term, and meaningful Social Security income reducing portfolio withdrawal pressure, something close to four percent may still be reasonable.

For someone retiring at fifty-five with a forty-year horizon, limited guaranteed income, significant healthcare spending, and a rental housing cost that has been inflating at five percent annually, the safe withdrawal rate from their portfolio alone is probably closer to three to three-and-a-half percent.

For someone already five years into retirement who experienced the 2022 combination of portfolio declines and high inflation simultaneously, the original four percent calculation may already be under stress and worth revisiting with current portfolio values and current spending reality.

The most important thing the four percent rule can do for you today is give you a starting framework for thinking about sustainability — not a number to follow mechanically without understanding the assumptions underneath it. Those assumptions — thirty-year horizon, historical average inflation, uncorrelated stock and bond performance — are all worth examining critically for your specific situation before deciding how much you can comfortably spend each year.

What a More Honest Approach Looks Like

Rather than applying the four percent rule mechanically, a more honest approach involves understanding your actual monthly spending by category, applying realistic inflation rates to each category based on how that specific category has actually been inflating, understanding what guaranteed income you have from Social Security or other permanent sources that reduces portfolio withdrawal pressure, and modeling how long your portfolio lasts under different withdrawal scenarios.

The question is not whether four percent is the right number. The question is what withdrawal rate keeps your specific portfolio intact long enough to support your specific spending with your specific income sources for your specific expected retirement length. That calculation is personal and it changes every time your portfolio balance changes, your spending changes, or your income changes.

Running that calculation once when you retire and never revisiting it is the real risk. Running it regularly — updating it with actual spending, actual portfolio performance, and actual income — is what turns retirement planning from a one-time guess into an ongoing honest picture of your financial health.