Safe Withdrawal Rate By Age Calculator

The classic 4% rule assumed a 30-year retirement. If you retire at 50, plan for 40-45 years. If you retire at 70, 4% is conservative. This calculator adjusts the safe withdrawal rate (SWR) for your specific time horizon and asset mix.

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Where The 4% Rule Came From

William Bengen's 1994 SAFEMAX study tested every 30-year retirement window from 1926-1976. A 4% inflation-adjusted withdrawal from a 50/50 stocks/bonds portfolio survived all scenarios — including the 1966 and 1929 worst-case starts. The 4% rule has held up across subsequent updates, but Morningstar's 2024 analysis suggests 3.7% under current bond yields and equity valuations.

Adjusting For Time Horizon

Longer horizons require lower SWR. A 50-year-old planning to age 95 has a 45-year retirement — Bengen's research suggests 3.3% is safer. A 70-year-old retiring with 20-25 year horizon can withdraw 5%+. The math is sensitive to sequence-of-returns risk: a 30% market drop in year 1 is catastrophic; a 30% drop in year 20 barely matters.

Sequence-Of-Returns Risk

Bad market years early in retirement permanently impair the portfolio because you sell low to fund withdrawals. Mitigations: hold 2-3 years of expenses in cash/bonds, use a bond tent that flattens at retirement, or use a guardrail strategy that reduces withdrawals after a 20% drop.

Source: Bengen SAFEMAX 1994, Trinity Study 1998, Morningstar State of Retirement Income 2024, Wade Pfau retirement researcher. Last updated: May 2026.