Your 401(k) was tax-deferred, not tax-free. Here's exactly how withdrawals are taxed once you retire.
How Are Traditional 401(k) Withdrawals Taxed?
Money in a traditional 401(k) was contributed pre-tax, so every dollar you withdraw in retirement is taxed as ordinary income at your federal marginal rate, plus state income tax where applicable. There are no special capital gains rates on these withdrawals. The amount you take out is added to your other income for the year and can push you into a higher bracket. Once you reach age 73, Required Minimum Distributions force you to withdraw a minimum amount annually, calculated from your balance and an IRS life-expectancy factor. Failing to take an RMD triggers a penalty, though SECURE 2.0 reduced it to 25%, or 10% if corrected promptly.
How Can I Reduce Taxes on 401(k) Withdrawals?
Several strategies soften the tax bite. Converting portions of your 401(k) or rolled-over IRA to a Roth during low-income years spreads the tax at lower rates and shrinks future RMDs. Coordinating withdrawals with other income keeps you in a target bracket. Qualified Charitable Distributions from an IRA after age 70 and a half satisfy RMDs tax-free. If you continue working past 73 and don't own 5% or more of the employer, you may delay RMDs from that specific employer's 401(k). Timing matters too: large lump-sum withdrawals can spike your bracket and your Medicare IRMAA surcharges, so spreading them out usually costs less.
How Do 401(k) Withdrawals Affect Medicare?
Because 401(k) withdrawals raise your taxable and modified adjusted gross income, they can increase Medicare IRMAA surcharges on Part B and Part D premiums two years later. Large RMDs are a common cause of unexpected premium jumps. Planning withdrawal size and timing protects you. The licensed agents at 1-800-MEDIGAP (1-800-633-4427) can explain how your retirement income affects your Medicare costs and help you coordinate coverage with your withdrawal plan.