Roth Conversion IRMAA Planner
A Roth conversion counts as income in the year you do it. Two years later, that income can move your Medicare Part B and Part D premiums into a higher IRMAA bracket. See how much room you have.
IRMAA works in steps. If your modified adjusted gross income (MAGI) goes over a threshold by even $1, your whole Part B and Part D premium moves to the next tier for the year. Medicare uses your income from two years earlier, so a conversion this year affects premiums two years from now. A Roth conversion adds to MAGI dollar for dollar. Enter your expected MAGI before the conversion and the amount you are thinking of converting to see which tier you would be in.
Most Roth conversion advice looks at your tax bracket. IRMAA has its own thresholds, and a conversion that looks small can raise your premium if it crosses one. This tool uses the same 2026 IRMAA brackets as our IRMAA Calculator and compares two figures: your MAGI before the conversion and after it.
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. Double these figures for the cost to your household.
Two separate sets of thresholds. Income tax brackets and IRMAA brackets both use MAGI, but they do not line up. A conversion that stays inside your tax bracket can still cross an IRMAA line. Crossing by $100 costs the same as crossing by $50,000: the premium for Part B and for Part D moves to the next tier's flat amount for all twelve months.
Example with 2026 brackets. A single filer has a MAGI of $100,000. The first threshold is $109,000, so there is $9,000 of room.
- Convert $9,000 or less: no surcharge.
- Convert $20,000: MAGI becomes $120,000, in the second tier. Part B rises from $202.90 to $284.10 a month and Part D gains a $14.50 surcharge. That is $95.70 a month, or about $1,148 for the year.
The surcharge lasts one year. If your income drops back below the threshold the next year, the premium goes back down.
Use the two-year gap. A conversion this year affects your premium two years from now. That gives you time to plan. Many people convert an amount each year that stays under the next threshold, over several years, instead of one large conversion that crosses several tiers. Conversions done at age 62 or younger do not affect Medicare premiums at all, because Medicare at 65 looks back only to age 63.
IRMAA is not a reason to avoid converting. The surcharge is usually small next to the tax a conversion can save later, especially if it shrinks future required minimum distributions, which also count toward IRMAA. The aim is to know the cost before you choose the amount.
The thresholds are adjusted for inflation each year. This planner uses the 2026 brackets, so treat the result for a future year as an estimate and leave a margin below the line.
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 takes your MAGI over an IRMAA threshold, your premiums rise two years later. Crossing a threshold by even $1 moves your whole 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, under the two-year lookback IRMAA always uses.
Does the IRMAA surcharge apply per person or per household?
Per person. If you are married and both of you are on Medicare, the surcharge shown here applies to each of you, so the cost to the household 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 compared with the long-term tax benefit of converting, especially if it avoids larger required minimum distributions later, which also count toward IRMAA. Run the numbers for your own case before deciding.
How is this different from the IRMAA Calculator?
The IRMAA Calculator shows your premium for one MAGI figure. This planner compares two figures, your MAGI before and after a proposed Roth conversion. It shows how much you can convert within your current tier and how much would move you into a higher one.
Uses the same 2026 IRMAA brackets as our IRMAA Calculator (CMS 2026 Medicare Costs fact sheet), applied to your MAGI before and after the conversion. It assumes the full conversion amount adds to MAGI and nothing else changes. It does not model the income tax on the conversion, state tax, or other changes in income. This is a planning estimate. Confirm your numbers with a tax professional before you settle on a conversion amount.