Roth Conversion IRMAA Planner
A Roth conversion is taxable income the same year it happens — and two years later, it can push your Medicare Part B and D premiums into a higher IRMAA bracket. See exactly how much room you have before that happens.
IRMAA is a cliff, not a gradual increase — crossing a MAGI threshold by even $1 moves your entire Medicare Part B and D premium to the next tier, and it applies two years later based on this year's income. A Roth conversion adds directly to that MAGI, so a conversion sized without checking your IRMAA brackets can trigger a much bigger premium jump than the conversion amount alone would suggest. Enter your expected MAGI before the conversion and the amount you're considering converting to see exactly where you'd land.
Most Roth conversion advice focuses on the tax bracket, but IRMAA has its own separate set of thresholds — and because it's an all-or-nothing cliff, a conversion that looks small can still trigger a large premium increase if it crosses a line. This tool uses the same verified 2026 IRMAA brackets as this site's IRMAA Calculator, applied to two MAGI figures at once: before and after your proposed conversion.
Plan Your Conversion
Your Conversion's IRMAA Impact
Before Conversion
After Conversion
Monthly Increase
If both you and your spouse are enrolled in Medicare, this surcharge applies to each of you individually — double these figures for your total household impact.
IRMAA thresholds and Roth conversion tax brackets are two completely separate systems that happen to both key off MAGI, which is exactly why they're easy to plan around independently and miss the interaction between them. A conversion that fits neatly inside your current federal tax bracket can still cross an IRMAA threshold, since the IRMAA brackets don't line up with the regular tax brackets at all. And because IRMAA is a cliff rather than a gradual scale, the cost of crossing a threshold by $100 is the same as crossing it by $50,000 — the entire premium jumps to the next tier's flat amount, for both Part B and Part D, for every month of that coverage year.
The two-year lookback is what makes this a genuine planning exercise rather than something you find out about after the fact. A conversion you do this year won't affect your premium until two years from now, which is exactly the window where multi-year Roth conversion planning can actually optimize around IRMAA — converting up to the top of your current bracket each year, for several years running, instead of doing one large conversion that jumps several tiers at once and pays the higher premium for longer than necessary.
None of this is a reason to avoid converting. IRMAA's dollar cost is usually small compared to what a Roth conversion can save in future taxes, especially if it reduces the size of required minimum distributions later, which have their own IRMAA exposure once they start. The point of this planner isn't to talk you out of converting — it's to make sure the IRMAA cost is a number you chose deliberately, not one you discovered on your Medicare premium notice two years later.
Frequently Asked Questions
Can a Roth conversion increase my Medicare premiums?
Yes. A Roth conversion adds the converted amount to your MAGI for that tax year, and Medicare uses MAGI from two years earlier to set your Part B and Part D premiums (IRMAA). If the conversion pushes your MAGI over an IRMAA threshold, your premiums increase two years later, and IRMAA is a cliff — crossing a threshold by even $1 moves your entire premium to the next tier.
When would a Roth conversion affect my premiums?
Two years later. A conversion done in 2026 would affect your Medicare premiums in 2028, based on the same two-year lookback IRMAA always uses.
Does the IRMAA surcharge apply per person or per household?
Per person. If you're married and both spouses are enrolled in Medicare, the surcharge shown by this planner applies separately to each of you — so the household impact of crossing a bracket can be double the per-person figure.
Is it ever worth paying more IRMAA to do a Roth conversion?
Often, yes — IRMAA is usually a small cost relative to the long-term tax benefit of converting, especially if it helps avoid larger required minimum distributions and their own IRMAA impact later. It's a genuine trade-off worth running the numbers on, not an automatic reason to avoid converting.
How is this different from the IRMAA Calculator?
The IRMAA Calculator shows your premium for a single MAGI figure. This planner compares two figures side by side — your MAGI before and after a proposed Roth conversion — so you can see exactly how much of the conversion is "free" within your current bracket and how much pushes you into a higher one.
Uses the same 2026 IRMAA bracket figures as this site's IRMAA Calculator (CMS 2026 Medicare Costs fact sheet), applied to a before/after MAGI comparison. Assumes the full conversion amount adds directly to MAGI with no other changes — it doesn't model the conversion's own income tax cost, state tax impact, or any other simultaneous income changes. This is a planning estimate — confirm your specific numbers with a tax professional before finalizing a conversion amount.