What is the 4% rule and does it still work?
In one paragraph
The 4% rule says retirees can withdraw 4% of their portfolio in year one, then adjust for inflation each year, with historically low odds of running out of money over a 30-year retirement. It still works as a starting benchmark, but lower expected returns and longer retirements have led many planners to suggest a 3–3.5% rate for added safety.
What this actually means
The 4% rule traces back to the 1994 "Trinity Study" and financial planner William Bengen, who analyzed decades of stock and bond returns to find a withdrawal rate that would survive even the worst historical market sequences. The conclusion: a balanced portfolio could sustain a 4% initial withdrawal, adjusted annually for inflation, through a 30-year retirement without depleting principal in the vast majority of scenarios.
The mechanics are straightforward. A retiree with $1 million withdraws $40,000 in year one. If inflation runs 3%, the year-two withdrawal becomes $41,200, and so on. The portfolio stays invested throughout, with growth theoretically offsetting withdrawals over time.
Why the debate? Critics point to three headwinds not present in Bengen's original dataset. First, bond yields have spent years at historic lows, compressing the fixed-income returns that historically cushioned equity downturns. Second, today's retirees routinely live into their 90s — a 30-year horizon is no longer guaranteed to be long enough. Third, sequence-of-returns risk (poor early returns permanently reducing the portfolio's ability to recover) is amplified when starting valuations are high.
Proponents counter that the rule has survived every historical bear market tested, including the Great Depression and the 1970s stagflation era. Morningstar and other researchers have periodically updated the analysis with recent data; the consensus lands somewhere between 3.3% and 4.5% depending on asset allocation and time horizon.
Practical adjustments that extend portfolio longevity include: using a flexible withdrawal approach that cuts spending slightly in down years, delaying Social Security to maximize lifetime income, maintaining a cash buffer to avoid selling equities at depressed prices, and shifting to a slightly more conservative allocation as retirement lengthens.
The 4% rule is best understood as a starting point for planning, not a guarantee. Running personalized projections with a financial planner — accounting for Social Security, part-time income, and spending flexibility — produces a more defensible number than any single rule of thumb.
