The Roth Conversion Window That Closes Faster Than Most 401(k) Savers Expect

This financial analysis article warns that retirees with large traditional 401(k) balances face a narrow window (ages 62-72) to convert to Roth IRAs before Required Minimum Distributions (RMDs) begin at age 73 under SECURE 2.0. Using a scenario of a 62-year-old with $1.5 million in a 401(k), the article projects the balance grows to $2.85 million by 73, forcing a $107,000 first-year RMD. This triggers a 'tax cascade' where ordinary income rates, Social Security taxation (up to 85% taxable), and IRMAA Medicare surcharges combine to create an effective marginal tax rate near 40%, even for those nominally in the 22% bracket. The article recommends converting up to $239,000 annually between 62 and 72 at the 22% rate to avoid being forced into higher brackets (24-32%) plus Medicare penalties starting at 73. It includes a sponsored section promoting SmartAsset's financial advisor matching service.