The RMD Trap That Quietly Costs Retirees Thousands in Medicare Premiums and How to Avoid It

A married couple, both 73, sitting on a $900,000 traditional 401(k) balance is about to take their first required distribution. The check itself is manageable, but the tax return it generates quietly pushes their modified adjusted gross income across the first IRMAA threshold, and their Medicare premiums two years from now go up with it.

The RMD That Starts the Chain Reaction

At 73, the IRS Uniform Lifetime Table divisor is 26.5. A $900,000 balance produces a required withdrawal of roughly $33,962, which rounds to $34,000. Taken in isolation it looks routine. Layered on top of Social Security, a small pension, and taxable interest and dividends from a brokerage account, it becomes the marginal dollars that trip the wire.

Assume combined Social Security of about $65,000 (with up to 85% taxable), a $40,000 pension, and $30,000 in taxable interest and dividends. Layering in the $34,000 RMD lifts MAGI close to the first IRMAA line. A year-end mutual fund capital gain distribution then pushes it over $218,000.

What Crossing the Line Actually Costs

Once joint MAGI moves into the first IRMAA tier, each spouse pays an extra $81.20 per month in Part B on top of the standard $202.90 premium, and a Part D surcharge is layered on as well. Two people, twelve months, and the couple has quietly added close to $2,000 in Medicare premiums for the year. The lookback is two years, so the 2026 tax return sets the 2028 bill. Most retirees don’t connect those dots until the Social Security notice arrives.

The problem compounds. At 75 the RMD divisor drops to 24.6. At 80 it’s 20.2. If the portfolio keeps growing at 5% to 6%, the required withdrawal climbs faster than spending needs, pushing taxable income higher just as the IRMAA tiers get harder to dance around.

The Cleanest Fix: Qualified Charitable Distributions

For a couple that already gives to charity, the QCD is the sharpest tool available. Money moves directly from an IRA to a qualified charity, counts toward the RMD, and is excluded from AGI entirely. It bypasses the top-line income figure that both IRMAA and Social Security taxation depend on, working outside the standard deduction framework.

If this couple already writes $15,000 a year in checks to their church and a community foundation, routing those gifts as QCDs shrinks the taxable RMD from $34,000 to $19,000. That single move keeps MAGI comfortably below the $218,000 threshold, cancels the roughly $2,000 IRMAA surcharge in 2028, and cuts the taxable portion of Social Security along the way. One caveat: QCDs must originate from an IRA. A 401(k) has to be rolled over first, and that rollover itself is not a taxable event.

The Second Lever, Only Available Earlier

For couples not yet 73, the more powerful move is to convert traditional balances to Roth in the gap between retirement and RMD age. Filling the 22% bracket (which runs to $206,700 for joint filers in 2025 and $211,400 in 2026) with $60,000 a year of conversions from 65 to 73 can pull nearly $480,000 out of the base the RMD is calculated against. That turns a $34,000 first RMD into something closer to $16,000, and it never triggers IRMAA in the first place. Once the RMD clock has started, though, the QCD does most of the heavy lifting.

Three Things to Do Before December 31

1. Project this year’s MAGI in October, not April. Add the RMD, taxable Social Security, pension income, interest, dividends, and any expected capital gain distributions. If the number is within $10,000 of $218,000, treat it as a planning problem that needs action before year-end.
2. Roll the 401(k) to an IRA before year-end if charitable giving is part of the plan. QCDs cannot come out of a 401(k), and there is no partial workaround. The rollover is a one-time paperwork exercise that unlocks the strategy for every year going forward.
3. File Form SSA-44 when a life-changing event (retirement, spouse’s death, divorce) has reduced income since the two-year lookback year. Medicare will recalculate the IRMAA based on current circumstances instead of the older return.

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