Can a Roth Conversion Increase Medicare Premiums? 2026 IRMAA Costs Explained

IRMAA means Income-Related Monthly Adjustment Amount. Beneficiaries whose MAGI exceeds the applicable threshold may pay an additional amount with Medicare Part B and an additional amount for Medicare prescription-drug coverage. The Part D IRMAA is added to the person’s separate Part D plan premium; it is not the plan premium itself. [1] [2]

IRMAA changes the premium, not the Medicare benefits received. Part B and Part D have separate adjustments, and the ordinary Part D plan premium remains separate.

Generally, the taxable portion does. IRS guidance says a traditional IRA amount that would have been included in income if distributed is generally included in gross income for the year it is converted. Because that amount generally affects AGI, it can also affect IRMAA MAGI. SSA defines IRMAA MAGI as AGI plus tax-exempt interest. [3] [8]

The gross transfer and taxable amount can differ. Valid nondeductible basis may make part nontaxable, but the calculation generally considers all applicable Traditional, SEP, and SIMPLE IRA balances.

Form 8606 reports nondeductible contributions, certain IRA distributions, and Roth conversions. [9] Review the Agent Roth explanation of how Roth conversions are taxed and the detailed guide to IRA basis and Form 8606 before assuming every converted dollar increases MAGI.

SSA generally uses the most recent federal tax information the IRS can provide, commonly from two years before the premium year. For 2026, that is generally a return filed in 2025 for tax year 2024. [2] [3]

If two-year-old data is unavailable, SSA may temporarily use three-year-old information and later update the determination. [4]

The standard 2026 Part B premium is $202.90 per month. The table below uses CMS figures for full Part B coverage and Part D IRMAA. The Part D amount is added to the beneficiary’s ordinary plan premium. These 2026 premiums generally use 2024 tax-return information.

CMS published these 2026 full Part B and Part D figures on November 14, 2025. [1] SSA also presents the general 2024-income lookback and current premium table. [2]

This married-filing-separately table applies when the beneficiary lived with the spouse at some time during the taxable year. Other filing and living arrangements require the applicable SSA table; they should not be collapsed into this special table.

For one beneficiary enrolled in both Part B and Part D for all 12 months, the first tier adds $81.20 of monthly Part B IRMAA and $14.50 of monthly Part D IRMAA. The combined incremental adjustment is $95.70 per month, or $1,148.40 for 12 months.

The calculation excludes the $202.90 standard Part B premium and the beneficiary’s ordinary Part D plan premium. It is incremental IRMAA only and assumes 12 months of enrollment in both coverages.

In this simplified educational example, a single Medicare beneficiary has $100,000 of 2024 MAGI before a $20,000 taxable Roth conversion. Illustrative MAGI becomes $120,000, which is above the first 2026 individual threshold of $109,000 and falls in Tier 1.

In this second simplified educational example, a married couple filing jointly has $210,000 of 2024 MAGI before a $20,000 taxable Roth conversion. Illustrative MAGI becomes $230,000, above the first 2026 joint threshold of $218,000. Both spouses are enrolled in Part B and Part D.

IRMAA analysis generally begins with the taxable income entering AGI, not automatically the gross transfer. Form 8606 and the pro-rata calculation may control, and all applicable Traditional, SEP, and SIMPLE IRA balances can matter. This simplified example is not a completed Form 8606 calculation. Read the full IRA basis and Form 8606 guide before treating the $10,000 as nontaxable. [9]

IRMAA is bracketed. Crossing a threshold can place a beneficiary in the next monthly surcharge tier rather than applying a percentage only to the income above the threshold. That step-up is why a relatively small MAGI difference can change a full year of monthly adjustments.

Projected MAGI remains an estimate. Conversion income, IRA basis, gains, interest, tax-exempt interest, taxable Social Security, business income, and other adjustments may move the final return. A narrow cushion can disappear.

Staying below a threshold is not automatically the best overall result. A household may accept a temporary premium adjustment within a broader retirement-tax decision. Measure the premium effect alongside current tax, future distributions, cash flow, and other objectives.

Generally, no—not under the normal two-year lookback. A 2026 conversion affects the 2026 tax year, while a standard 2026 IRMAA determination generally uses 2024 income. The taxable 2026 conversion would generally become relevant for 2028 premiums.

That does not mean the 2028 result can be calculated today. Future thresholds, the standard Part B premium, Part D adjustments, tax-return information, filing status, and enrollment may differ. The 2026 figures are current facts for 2026 premiums, not a forecast.

Yes, when a joint return supplies the MAGI and both spouses are enrolled in the affected Medicare coverage. IRMAA is charged per Medicare beneficiary. If both spouses have Part B and Part D, each may owe both adjustments at the joint-return tier.

If only one spouse is enrolled in Part B, only that beneficiary pays the Part B adjustment. The same coverage-specific rule applies to Part D. Filing status and living arrangements determine which threshold table applies, so married filing separately should not be treated as ordinary “individual” filing without checking the SSA rules.

SSA generally recalculates IRMAA for each premium year. A one-time conversion may primarily affect the premium year tied to that conversion year’s return, while later premium years generally use later returns. Continuing conversions or other high income can produce adjustments in multiple years, and amended or corrected tax information may change a determination. A conversion should not be described as affecting exactly one year in every case.

A Roth conversion alone generally is not one of the qualifying life-changing events for an SSA-44 request. SSA’s list of qualifying events is exclusive, and SSA notices explain that MAGI may contain one-time income such as an IRA withdrawal or traditional-to-Roth conversion. [6] [7]

A beneficiary may have a separate qualifying event: marriage; divorce or annulment; death of a spouse; work stoppage; work reduction; certain loss of income-producing property; certain loss or reduction of employer pension income; or certain employer settlement payments. A genuine event that reduces household income may support a request for SSA to use more recent information, but SSA evaluates the facts and evidence.

Different processes address different problems. A qualifying event may support a new initial determination. Inaccurate IRS information can be corrected. An amended return can be reported to SSA. A person who disagrees with SSA’s determination can use the appeal process. Filing Form SSA-44 does not guarantee a reduction. [10] [5]

Stopping work or reducing work hours can be a qualifying life-changing event when it reduces income. The work change—not the conversion—is the event. SSA considers the request, supporting evidence, and newer MAGI information under its process.

Retirement does not automatically remove conversion income from MAGI. If a beneficiary provides an updated income estimate that includes a large taxable conversion, that conversion may still be part of the newer MAGI. The request needs to reflect the full expected income picture rather than wages alone.

Use this educational lookup to compare a 2024 MAGI with the exact CMS 2026 table. It estimates only the incremental Part B and Part D IRMAA for the selected enrollment counts. It does not determine taxable conversion income or produce an official SSA premium decision.

1. Identify the proposed conversion tax year.
2. Identify which Medicare premium year may generally use that return.
3. Estimate AGI before the conversion.
4. Determine the expected taxable conversion amount.
5. Include capital gains, pensions, RMDs, interest, and other income.
6. Add tax-exempt interest when calculating IRMAA MAGI.
7. Confirm filing status.
8. Identify how many spouses will be enrolled in Part B.
9. Identify how many spouses will be enrolled in Part D.
10. Compare the result with the correct official threshold table.
11. Leave room for uncertain year-end income.
12. Compare the premium effect with the broader tax and retirement-account result.

1. Using gross income instead of IRMAA MAGI.
2. Forgetting tax-exempt interest.
3. Treating the conversion year as the premium year.
4. Using 2026 thresholds as a guaranteed 2028 result.
5. Looking only at the Part B adjustment.
6. Forgetting the separate Part D adjustment.
7. Counting one spouse when both are enrolled.
8. Calling IRMAA an income tax.
9. Assuming every Roth conversion is fully taxable.
10. Assuming retirement automatically removes IRMAA.
11. Treating every SSA request as an appeal.
12. Letting one threshold control the entire conversion decision.

• The taxable portion of a conversion can increase AGI.
• IRMAA MAGI generally includes AGI plus tax-exempt interest.
• Medicare generally looks back two tax years.
• A 2024 conversion may affect 2026 premiums.
• A 2026 conversion would generally be relevant to 2028 premiums.
• A Roth conversion alone is generally not an SSA-44 qualifying life-changing event.

For evergreen mechanics, read the Roth conversion and IRMAA guide. For the timing of the related tax payment, review the current Brief on when Roth conversion taxes are due.