Quick Answer:
Yes, a Roth conversion can raise your Medicare premiums, but not right away. The surcharge, called IRMAA, is based on your income from 2 years earlier, so a conversion today can raise your premiums 2 years later. It’s a cliff: crossing a threshold by even $1 triggers the full surcharge. Often the long-term tax savings still outweigh the bump.
Key takeaways:
– Roth conversions raise your income, which can trigger IRMAA, the income-related surcharge on Medicare premiums.
– IRMAA uses a 2-year lookback, so a 2026 conversion affects your 2028 premiums.
– IRMAA is a cliff, not a slope: going $1 over a threshold triggers the entire surcharge tier.
– A 1-year premium increase is often worth it if the conversion saves more in lifetime tax; the key is to convert deliberately.
Roth conversions are one of the best moves in retirement, but they have a side effect people miss: they can raise your Medicare premiums. The link isn’t obvious, because the bill doesn’t arrive until 2 years later. Here’s how it works and how to decide when it’s worth it.
How do Roth conversions affect Medicare premiums?
Roth conversions affect Medicare premiums because a conversion adds to your taxable income, and your income determines whether you pay an IRMAA surcharge. IRMAA, the income-related monthly adjustment amount, is an extra charge added to your Medicare Part B and Part D premiums once your income passes certain thresholds. Since a conversion increases your income for the year, a large one can push you over a threshold and raise your premiums.
The base Part B premium for 2026 is $202.90 per month, per Medicare.gov. If your income triggers IRMAA, you pay that base plus a surcharge on top, and a separate surcharge is added to your Part D drug plan too. For everyone on Medicare, this is worth understanding before converting.
What is the 2-year lookback?
The 2-year lookback means your Medicare premiums are set using your income from 2 years earlier. Your 2026 premiums are based on the income you reported for 2024, and a Roth conversion you do in 2026 will affect your premiums in 2028. This delay is what catches people off guard, because the higher premium shows up long after the conversion is forgotten.
The lookback cuts both ways. It means you have to plan ahead, but it also means a single high-income year only affects premiums for 1 year, 2 years down the road, and then they reset. That temporary nature is central to deciding whether a conversion is worth the surcharge.
What are the 2026 IRMAA thresholds?
IRMAA is tiered, and each tier adds a fixed amount to your Part B premium. Here are the 2026
Part B figures for a married couple filing jointly, based on 2024 income.
| 2024 Income (Married Filing Jointly) | 2026 Monthly Part B Premium |
|---|---|
| $218,000 or less | $202.90 (no surcharge) |
| $218,001 to $274,000 | $284.10 |
| $274,001 to $342,000 | $405.80 |
| $342,001 to $410,000 | $527.50 |
| $410,001 to $750,000 | $649.20 |
| Above $750,000 | $689.90 |
For single filers, the thresholds are roughly half these amounts, starting at $109,000. A Part D surcharge applies at the same income tiers. The full landscape is covered in IRMAA 2026 the medicare surcharge and how do you avoid IRMAA in retirement.
Why is IRMAA a cliff and not a gradual increase?
IRMAA is a cliff because crossing a threshold by even a single dollar triggers the entire surcharge for that tier. Unlike income tax brackets, where only the income above a line is taxed at the higher rate, IRMAA jumps all at once. Go $1 over the $218,000 line and your full monthly premium rises to the next tier, for both spouses, for the whole year.
This cliff structure is exactly why conversion sizing matters so much. A conversion that lands you $500 over a threshold costs the same IRMAA surcharge as one that lands you $5,000 over. When you plan a conversion near an IRMAA line, the goal is to stop just below it, or commit fully to the next tier for a clear reason. Sizing the conversion around these lines is covered in how much should you convert to roth each year.
When is triggering IRMAA still worth it?
Triggering IRMAA is worth it when the long-term tax savings from the conversion exceed the temporary premium increase. A conversion that moves a large sum out of a traditional IRA at today’s rates can save far more over your lifetime than a 1-year, 2-years-later bump in premiums costs. The surcharge is annoying, but it’s small and temporary next to decades of tax-free Roth growth and lower future RMDs.
The mistake is letting IRMAA scare you out of converting entirely. The right approach is to weigh the surcharge as one cost among several, not treat it as a hard stop. Sometimes stopping just below a threshold is smart; sometimes pushing into the next tier is clearly worth it. The point is to decide on purpose, with the full math in front of you, rather than stumbling across the line by accident. A good rule of thumb is to weigh the 2-year premium cost against the lifetime tax saved before you convert. When the savings dwarf the surcharge, as they often do for a large traditional balance, the temporary bump is a price worth paying.
Frequently Asked Questions
Does a Roth conversion raise my Medicare premium the same year?
No. Because of the 2-year lookback, a conversion this year affects your premiums 2 years later, then they reset. A 2026 conversion shows up in your 2028 premiums.
How much can IRMAA add to my Medicare costs?
It varies by tier and can add hundreds of dollars per month per person across Part B and Part D combined. For a married couple, both spouses pay the surcharge, so the annual cost of crossing a tier can be significant, though it lasts only 1 year per high-income year.
Can I appeal an IRMAA surcharge?
Yes, if you’ve had a qualifying life-changing event such as retirement, the death of a spouse, or a large drop in income. You file Form SSA-44 with documentation. A Roth conversion by itself is not a qualifying event, so you can’t appeal a surcharge caused by choosing to convert.
Should I avoid Roth conversions to stay under IRMAA?
Not necessarily. For many retirees the lifetime tax savings outweigh a temporary premium increase. The goal is to convert deliberately around the thresholds, not to avoid converting because IRMAA exists.
IRMAA is a real cost of Roth conversions, but it’s a manageable one once you can see the thresholds and the 2-year timing. If you’d like to plan conversions that respect the IRMAA cliffs, request a meeting and we’ll map it around the lines.
About the Author
Kurt Supe, CPA, is a Retirement Planner and Chief Investment Officer for Creative Financial Group. He has spent 30 years helping retirees lower their lifetime tax bills. Connect on X and YouTube at @KurtSupeCPA, or read more on the CFG team page.