Do Roth Conversions Trigger IRMAA?
$1,148 a year. That is roughly what a single dollar of extra income costs you in 2026 if it pushes your MAGI one dollar over the first IRMAA threshold. Not a typo. Do Roth conversions trigger IRMAA? Yes, because every converted dollar lands on your tax return as ordinary income in the year you convert, and Medicare's two-year lookback means a conversion at 65 raises your Part B and Part D premiums at 67. The surcharge is a cliff, not a slope: one dollar over the line buys the entire tier for the full year. Here is the choice, the rules, and the one case where paying the surcharge anyway is the right call.
How a Roth conversion triggers IRMAA
The mechanism has three steps and no exceptions. Step one: the conversion adds to your modified adjusted gross income in the conversion year. Step two: two years later, Medicare checks that tax year's MAGI against the IRMAA brackets. Step three: if you crossed a threshold by any amount, you pay that tier's surcharge every month for the year.
For 2026, the single-filer brackets run: $109,000 or less pays the standard premium; $109,001 to $137,000 adds $81.20 a month in Part B; $137,001 to $171,000 adds $202.90; $171,001 to $205,000 adds $324.60; $205,001 to $500,000 adds $446.30; above $500,000 adds $487.00. Joint thresholds are double. Each tier also carries a Part D surcharge on top, which is how one dollar over $109,000 single becomes roughly $1,148 a year per person in combined surcharges.
The decision rules
If you are under 63, convert freely. IRMAA looks back two years and Medicare starts at 65, so the first tax year it ever sees is the year you turn 63. A conversion at 62 lands in a tax year Medicare never examines for your initial premiums. The years between retirement and 63 are the widest-open conversion window most people will ever get. Use them.
If you are 63 or older, convert to the line, not past it. Project your base MAGI for the year first, then size the conversion so total MAGI lands just under the next threshold. There is no rounding mercy: $109,000 is clean, $109,001 is Tier 1. Run the numbers in October or November, when the year's income is nearly final, rather than guessing in January. Late-fall conversions give you the clearest picture of the line.
If the conversion is large enough, pay the tier on purpose. This is the case where the conventional wisdom, never trigger IRMAA, gets it wrong. A $30,000 conversion on a $200,000 base MAGI lands at $230,000 joint, Tier 1, with about $2,297 in annual surcharges for the couple. If that conversion saves roughly $7,200 in federal tax at 24%, the math still wins: a one-year surcharge against decades of tax-free growth. What rarely pays is jumping two tiers in one year. Cross one line deliberately; do not stumble over two.
If you are married, model the widow's penalty before you size anything. When one spouse dies, the survivor files single the following year, and the thresholds halve: $218,000 joint becomes $109,000 single. Conversions sized comfortably under joint thresholds can slam the survivor into surcharges. This is the trap I see skipped most often in conversion plans built for couples.
Where the planning usually goes wrong
Two mistakes account for most of the damage. The first is converting in the 22% or 24% bracket to beat future required minimum distributions, without checking the IRMAA tiers. The conversion is sound tax planning, and the surcharge arrives two years later as a surprise line on the Medicare premium notice. Morningstar's reporting on this put it well: a conversion in the 24% bracket can effectively cost closer to 29% once IRMAA is folded in. The second mistake is treating the threshold as approximate. It is exact to the dollar. The two-year lookback and what counts toward IRMAA MAGI are the two companion reads if you want the full mechanics; the short version is that muni-bond interest counts, qualified Roth withdrawals do not, and managing MAGI is a year-round exercise, not a December scramble.
Frequently Asked Questions
Do Roth conversions trigger IRMAA?
Yes. Every dollar converted from a traditional IRA to a Roth counts as ordinary income in the conversion year, raising your MAGI. Medicare's two-year lookback means a conversion at 65 raises your premiums at 67. In 2026, going $1 over the $109,000 single or $218,000 joint threshold adds roughly $1,148 a year per person in combined Part B and Part D surcharges.
At what age do Roth conversions stop triggering IRMAA?
Conversions before age 63 normally carry no IRMAA risk, because IRMAA looks back two years and Medicare starts at 65, so the first tax year it sees is the year you turn 63. Convert at 62 and the income lands in a tax year Medicare never examines for your initial premiums.
Can Form SSA-44 undo IRMAA from a Roth conversion?
No. Form SSA-44 requests a new determination based on a life-changing event like retirement, marriage, divorce, or death of a spouse. A voluntary Roth conversion is not a qualifying event, so the surcharge stands for the year. There is no undo button after December 31 of the conversion year.
Is it ever worth paying IRMAA to do a larger Roth conversion?
Sometimes. A conversion saving $7,200 in federal taxes while triggering $2,297 in IRMAA surcharges for one year is still a net win, because the tax saving compounds for decades while the surcharge lasts one year. Compare the one-time surcharge against the lifetime tax-free growth, and avoid jumping two tiers at once.
What is the widow's penalty with IRMAA and Roth conversions?
When one spouse dies, the survivor files as single the year after, halving the IRMAA thresholds, from $218,000 joint to $109,000 single in 2026. Conversions sized for joint thresholds can suddenly trigger surcharges for the survivor. Model the single-filer scenario before sizing conversions as a couple.
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