The answer on these inputs
$500,000 produces $20,000 in year one at 4.0%. Against $32,000 of spending that is 63% coverage — the spend is larger than a 4% (or chosen) withdrawal. A constant 5.0% return exhausts the portfolio in year 21. Across 1,000 seeded paths the spend lasts the full horizon in 9% of worlds; the 10th-to-90th ending range is $0 to $0.
Change the inputs
First-year income at the rate$20,000
Coverage of the spend63%
Years the spend lasts21
1,000-path success9%