A 58 Year Old With $2.2 Million in a 401(k) Has Five Years to Execute the Roth Conversion That Saves $315,000 in Lifetime Taxes

A high-income worker with a large traditional 401(k) faces a choice about when to convert to Roth. Converting while still working at age 58 often results in higher taxes because each converted dollar adds to W-2 income and can push income into higher brackets. Waiting until after the paycheck stops allows conversions to fill lower tax brackets. A retirement at 63 creates a favorable tax corridor before required minimum distributions begin at 73. A plan of converting about $80,000 per year for ten years targets the 12% bracket and part of the 22% bracket, producing an estimated blended federal tax rate near 17% and about $136,000 in conversion taxes. Doing nothing allows the account to grow and leads to much higher taxes from RMDs, estimated around $451,000.

"At 58 and still working in the 24% bracket, converting traditional dollars to Roth is mostly a bad trade. Every converted dollar stacks on top of W-2 income. For a married couple filing jointly in 2026, the 24% bracket runs from roughly $207,000 to $395,000, and a high earner is already sitting inside it. A $100,000 conversion today costs $24,000 in federal tax and may push state tax higher."

"Wait until the paycheck stops, and the same conversion runs through the 12% bracket (up to roughly $97,000) and the 22% bracket (up to roughly $207,000) instead. That arithmetic is the foundation of bracket-filling research from Wade Pfau and Michael Kitces, and it is why the answer for this reader is to delay."

"Retirement at 63 opens a corridor that closes when RMDs start at 73. Social Security can be deferred. The 401(k) is the only large income source. That is the cleanest tax environment a high earner will ever see."

"The target plan: convert roughly $80,000 per year for ten years, $800,000 total. Stacked on minimal other income, those conversions fill the 12% bracket and spill into the lower half of the 22% bracket. The blended federal rate lands near 17%, for a total conversion tax of about $136,000."

Read at 24/7 Wall St.