Medicare IRMAA Roth Conversion Impact Planner

Roth conversions and Medicare IRMAA premium cliffs

A Roth IRA conversion can replace future taxable withdrawals with tax-free Roth assets, but it also raises the income reported for the conversion year. That additional modified adjusted gross income (MAGI) can affect Medicare’s income-related monthly adjustment amount, known as IRMAA. Medicare generally uses a tax return from two years earlier to set these surcharges, so income created by a conversion may increase later Part B premiums and Part D surcharges. A conversion that looks attractive on an income-tax projection can therefore create a separate Medicare expense that deserves a place in the decision.

Roth conversion planning often starts with federal income-tax brackets or future required minimum distributions. Medicare IRMAA adds another set of income breakpoints. Crossing a breakpoint can move an enrollee to a higher premium tier for the applicable year, even when the conversion exceeds the threshold by only a small amount. This planner lets you compare the Medicare effect of the conversion with your starting MAGI, helping you consider whether to stay below a threshold, accept a higher tier, or divide conversions among tax years.

This Roth conversion IRMAA planner combines your projected MAGI before the conversion with the proposed conversion amount and filing status. It identifies the applicable Part B premium and Part D surcharge under the included 2024 schedule, then shows the resulting monthly Medicare amount after adding the Part D plan premium you enter. The result also annualizes the change in IRMAA surcharges and can extend that difference across the number of years you expect to repeat the same pattern.

Introduction: Understanding Roth conversion IRMAA brackets

Roth conversion IRMAA exposure depends on MAGI and filing status. The calculator uses the listed 2024 IRMAA thresholds and premium amounts for single filers, married couples filing jointly, and married filers who lived with a spouse. Each income tier corresponds to a Part B premium and a Part D surcharge. The base Part B premium in the included schedule is $174.70 per month. Higher tiers use Part B premiums of $244.60, $349.40, $454.20, $559.00, and $594.00, while the listed Part D surcharges range from $12.90 to $81.00 per month. These are tiered amounts rather than percentages of the conversion.

The Roth conversion calculation adds the proposed conversion to projected MAGI before the conversion. For example, a single filer with projected MAGI of $95,000 who converts $60,000 has projected MAGI of $155,000 for this comparison. Under the included schedule, that amount falls in the tier with a $349.40 monthly Part B premium and a $33.30 monthly Part D surcharge, rather than the base tier. Relative to the base tier, the annual Part B surcharge is $2,096.40 and the annual Part D surcharge is $399.60. Whether that cost is worthwhile depends on tax effects and retirement goals that this Medicare-focused tool does not calculate.

For this Roth conversion IRMAA planner, the premium is a step-function result: the combined Medicare amount is selected from the tier associated with MAGI and filing status. Let M represent MAGI, let T_i represent a filing-status threshold, and let B_i and D_i represent the Part B premium and Part D surcharge for tier i. The calculator’s tiered monthly amount is:

The Roth conversion IRMAA output separates the monthly Medicare amount from annual IRMAA cost. The monthly total includes the Part B premium, the Part D surcharge, and your entered Part D plan premium. The annual IRMAA figure measures only the Part B amount above the $174.70 base premium plus the Part D surcharge, multiplied by twelve.

Worked example: comparing a Roth conversion with the next IRMAA threshold

Consider a couple filing jointly with projected MAGI of $180,000 before a Roth conversion. With no conversion, their MAGI is below the $206,000 threshold in the included joint-filer schedule, so the calculator shows the $174.70 base Part B premium and no Part D surcharge. A proposed $160,000 conversion raises projected MAGI to $340,000. That amount falls in the tier with a $454.20 Part B premium and a $53.80 monthly Part D surcharge for each enrollee. If both spouses are enrolled in Parts B and D, the increase from the base Part B premium is $6,708.00 per year across both people, and the Part D surcharges total $1,291.20 per year.

For this couple, the calculator’s threshold row identifies the largest conversion that remains at the next applicable limit from their starting MAGI: $26,000, bringing MAGI to $206,000. The comparison table then places that threshold-limited scenario beside no conversion and the proposed $160,000 conversion. That view does not determine the best tax strategy, but it makes the Medicare trade-off visible before the conversion is executed. A household considering repeated conversions can test separate amounts and years rather than assuming that one large conversion and several smaller conversions create the same IRMAA outcome.

Reading the Roth conversion IRMAA comparison table

The Roth conversion comparison table beneath the form shows how the entered conversion changes MAGI, the selected Part B premium, the Part D surcharge, and annual IRMAA cost. The no-conversion row anchors the comparison at your projected pre-conversion MAGI. When the proposed conversion would cross the next threshold, the middle row shows the largest amount that reaches that threshold under the calculator’s schedule. The final row displays the conversion you entered.

Reading the Roth conversion IRMAA rows together highlights the tiered nature of the premiums. Conversion amounts that remain in the same tier can produce identical IRMAA premiums even though their MAGI differs. Conversely, an amount that crosses a tier boundary can change the annual surcharge substantially. The downloadable CSV contains the same displayed scenarios, which can be retained with a tax projection or shared with a qualified adviser.

Putting Roth conversion IRMAA results in context

The Roth conversion IRMAA result explains the projected MAGI after the conversion, the resulting tier, and the change in monthly Medicare premiums. It also reports the annual difference in IRMAA cost and, when you enter more than one analysis year, multiplies that annual difference by the number of repeated years. Its effective marginal Medicare-cost figure divides that multi-year surcharge difference by the proposed conversion amount; it is not an income-tax rate and does not include federal or state tax generated by the conversion.

Roth conversion IRMAA estimates should be considered alongside circumstances that may change before Medicare sets the premium. Medicare generally relies on income from two years before the premium year. If a qualifying life-changing event causes income to fall, an affected beneficiary may be able to request a new determination through Form SSA-44. This calculator does not decide whether an appeal will be approved; it simply illustrates the scheduled premium effect of the income assumptions entered here.

Limitations and Roth conversion IRMAA planning assumptions

This Roth conversion IRMAA calculator uses the 2024 thresholds and premiums embedded in the page, which can change in later years. It assumes the projected MAGI and conversion are measured in current-year dollars and that the conversion is included in the MAGI used for the IRMAA comparison. For married filing jointly, the displayed per-person premiums apply to each enrolled spouse; a household with only one person enrolled in Medicare Parts B or D would not have two sets of premiums.

Roth conversion IRMAA planning also requires information outside this tool. The calculator does not calculate federal or state income tax on the conversion, future tax rates, Social Security taxation, investment performance, required minimum distributions, or the outcome of an IRMAA appeal. It assumes a surcharge applies for the full premium year represented by the comparison. Use the result as a Medicare-cost scenario, then coordinate it with a broader tax and retirement analysis before making an irreversible conversion.

How to use this Roth conversion IRMAA planner

1. Select Filing status so the planner uses the appropriate IRMAA threshold schedule.
2. Enter Projected modified AGI without the conversion (current year dollars) before adding the Roth conversion.
3. Enter the Proposed Roth conversion amount this year, along with your monthly Part D plan premium and the number of years you expect to repeat the pattern.
4. Evaluate the Roth conversion IRMAA impact, then test a different conversion amount to see whether it changes the Medicare tier before you act.