Can a Roth Conversion Increase Your Medicare Premiums?

Yes. A Roth conversion can increase your Medicare premiums. The converted amount is taxable income in the year you convert. Medicare’s income-related monthly adjustment amount, IRMAA, uses modified adjusted gross income from two years earlier. A conversion in 2026 does not change the premium you pay in 2026. It can change the premium in 2028.

Florida does not tax the conversion at the state level. The federal tax and the Medicare surcharge still apply.

The 2026 Part B brackets

CMS set the standard 2026 Part B premium at $202.90 a month. You pay that if 2024 MAGI was $109,000 or less (single) or $218,000 or less (married filing jointly). Cross the line and the premium steps up for the whole year.

Part D has its own IRMAA on top of the drug-plan premium. The first joint tier adds $14.50 a month per person in 2026. These figures are for full Part B coverage. Married filing separately uses a different, harsher scale.

A simple example

A married couple, both on Medicare, with joint MAGI of $200,000 before any conversion. They are under the $218,000 line, so each pays $202.90 for Part B.

They convert $30,000 from a traditional IRA to a Roth IRA. Joint MAGI becomes $230,000. That is the first IRMAA tier. Each pays $284.10 instead of $202.90. The extra is $81.20 a month, times two people, times 12 months: about $1,949 for the year the surcharge applies. Part D can add more.

The $30,000 is also ordinary income on the federal return in the year of the conversion. The Medicare cost shows up two years later. Both numbers belong in the decision.

What changes the answer

• Age and the two-year lookback. A conversion at 63 can hit premiums at 65, the year Medicare starts. A conversion at 68 hits premiums at 70.
• Filing status. Joint brackets are not double the single brackets at every tier. Married filing separately is much less forgiving above $109,000.
• Other income in the same year. A property sale, a large IRA withdrawal, or the start of Social Security can use up the room you thought the conversion had.
• One dollar over the line. IRMAA is a cliff. $218,001 joint MAGI is not “a little over.” It is the next premium for the full year.

The common mistake

People convert in the same year they start Medicare and expect the premium to change immediately, or they skip the conversion entirely because they heard IRMAA is a penalty. The useful window is often the years after the paycheck stops and before Social Security and required minimum distributions begin at 73. Income is temporarily low. A planned conversion fills that bracket. The mistake is sizing the conversion with the tax bracket only and ignoring the Medicare line two years out.

Questions to ask before you convert

• What was my MAGI two years ago, and what will this year’s MAGI be with the conversion included?
• Will both of us be on Medicare in the year IRMAA would apply?
• How close is that MAGI to the next joint threshold?
• What tax do I pay on the conversion this year, and what RMD tax might I avoid later?
• Is there a life-changing event (work stoppage, marriage, divorce) that Social Security can use to appeal IRMAA?

When a planner should run the numbers

Run them when the conversion is large enough to cross a bracket, when both spouses will be on Medicare, or when you are within two years of starting Social Security. The coordination of income, Medicare, and withdrawals is the work on our retirement income planning page.

This is education, not a recommendation to convert or to skip a conversion. Your return, your MAGI, and your Medicare year decide it.

If you want that comparison before you move IRA money, request a retirement readiness review.