Safe Withdrawal Rate Calculator
The 4% rule says retirees can withdraw 4% of starting portfolio annually (adjusted for inflation) and not run out over 30 years. Updated research (Big ERN, Morningstar) suggests 3.3-3.7% for early retirees with longer horizons.
Origin Of The 4% Rule
Trinity Study (1998) examined 1926-1995 US historical returns. A retiree withdrawing 4% of starting portfolio (adjusted annually for inflation) from a 60% stock/40% bond portfolio had 95%+ success over 30 years. Failure cases typically happened when retirement started just before a sequence-of-returns disaster (1929, 1966, 1973).
Why 4% May Be Too High For Early Retirees
FIRE community plans for 50+ year retirements (retire at 35, plan to age 85+). 4% works for 30 years; for 50-60 years sequence risk compounds. Big ERN (Karsten Jeske) analysis: 3.3-3.5% is the 50-year-horizon equivalent of 4% over 30 years. Morningstar 2024 study: 3.7% with conservative assumptions, 4.2% with global equity diversification.
Guard Rails Approach
Static 4% withdrawal ignores market signals. Guyton-Klinger guard rails: if portfolio falls 20% below initial real value, cut withdrawal by 10%. If portfolio rises 20% above initial real value, increase withdrawal by 10%. This dynamic rule allows starting withdrawal of 5-5.5% with similar 30-year safety as static 4%.
Source: Trinity Study (Cooley, Hubbard, Walz 1998), Big ERN SWR Series, Morningstar 2024 Income Planning Study. Last updated: May 2026.