The $39,200 Tax Cost That Saves $100,000 Later: A 401(k) Strategy for 60-Year-Olds

"Routing the $24,500 annual employee deferral into a Roth 401(k) instead of pre-tax costs her roughly $7,840 in additional federal tax each year at the 32% marginal rate, or about $39,200 across five years. That is the real out-of-pocket cost. She writes a larger check to the IRS through 2030. The deferral feels like free money because it shrinks today's bill. In practice it is a loan from the government, repayable at whatever rate Congress sets when she withdraws. For someone who will spend retirement in the 22% to 24% bracket, deferring at 32% can still pencil out. The break-even gets shakier once required minimum distributions, Social Security taxation, and IRMAA Medicare surcharges enter the picture."

"Five years of $24,500 contributions compounded at 7% grows to roughly $145,000 by age 65. Left to compound another 20 years through age 85, that balance becomes about $455,000. In a Roth 401(k), every dollar of that $455,000 comes out tax-free after 59½ with the five-year clock satisfied. In a traditional 401(k), the same $455,000 faces ordinary income tax at withdrawal, costing $100,000 to $110,000 in lifetime tax at a 22% to 24% RMD-era rate."

"The upfront cost is roughly $39,200. The avoided tax is closer to $100,000. That gap widens if inflation pushes her into a higher retirement bracket. Core PCE has continued climbing through early 2026, well above the Fed's 2% target. Tax brackets adjust for inflation slowly; spending power erodes faster. The SECURE 2.0 Rule That"

A single filer age 60 with $250,000 of W-2 income and about $2.1 million in a traditional 401(k) plans to retire in five years. Continuing pre-tax deferrals at a 32% marginal rate provides a deduction but creates a future tax liability when withdrawals occur. Routing the next five years of $24,500 annual contributions into a Roth 401(k) increases federal taxes now by about $7,840 per year, or roughly $39,200 total. The tradeoff is tax-free withdrawals after age 59½ if the Roth rules are satisfied. Traditional withdrawals would be taxed as ordinary income, with lifetime tax estimated around $100,000 to $110,000 during the RMD-era. The advantage grows with inflation, which can raise retirement tax brackets slowly while spending power erodes faster, and with factors like RMDs, Social Security taxation, and IRMAA Medicare surcharges.

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