Can a Roth Conversion Affect Health Coverage Costs?
A lower-income year can look like a good opening
An early retirement year can look unusually quiet on paper. Paychecks may have stopped. Social Security may not have started. Required distributions may still be years away. After decades of watching income arrive regularly, that quieter year may feel like a rare opening. [1][2]
That is often when a Roth conversion comes up. A conversion moves money from a tax-deferred retirement account to a Roth account. The converted amount is generally included in taxable income for that year. [2]
The usual comparison is whether paying tax now is preferable to paying tax when the money is withdrawn later. If health coverage costs depend on income, another question arises: what else could the conversion change? [3][4][5][6]
What changes when conversion income appears?
A Roth conversion can raise adjusted gross income for the year. It may affect the tax calculation, and its impact may not end with the tax return.
Marketplace premium tax credits use a form of modified adjusted gross income. HealthCare.gov explains that the calculation begins with adjusted gross income and adds certain items. Those additions may include tax-exempt interest and nontaxable Social Security benefits. [3]
Household income can also include a spouse’s income. It may include a dependent’s income when that dependent is required to file a tax return. That means the useful comparison is not limited to the conversion amount by itself. [3][5]
How could this affect Marketplace coverage?
Marketplace assistance may lower the premium paid during the year. The final premium tax credit is reconciled using annual income on the federal tax return. If the household received more advance credit than the final calculation allows, some of that amount may need to be repaid. [4]
HealthCare.gov tells consumers to report income changes because those changes can affect coverage assistance. A Roth conversion that increases annual income may therefore require an updated Marketplace estimate. [3][4][5]
This does not make the conversion automatically helpful or harmful. It means the conversion amount and the coverage estimate should be reviewed together. A smaller conversion or a different conversion year may produce a different household result. [2][4][5]
How could this affect Medicare premiums later?
Higher-income Medicare beneficiaries may pay income-related monthly adjustment amounts, commonly called IRMAA. These amounts are added to Part B and Part D costs. [6][7]
The timing can be easy to miss. Medicare commonly uses tax information from two years earlier when determining IRMAA. A one-time conversion can therefore affect Medicare premiums in a later year. [6][8]
For 2026, CMS announced a standard Part B premium of $202.90 and a Part B deductible of $283. CMS also published the 2026 income-related amounts. Those figures do not determine whether a conversion is appropriate. They show why Medicare costs belong in the review. [7]
Decision Guide: Should we do a Roth conversion while income is lower?
Why does the conversion amount matter?
Research has found that taxpayers often convert during lower-tax years and frequently convert only part of an IRA. The practical decision is often not whether to convert everything or nothing. It is the amount of income to recognize in a particular year. [1]
A partial conversion allows several amounts to be compared. One amount may create a manageable tax result. A larger amount may change Marketplace assistance or increase future Medicare premiums. [1][2][4][6]
The life situation matters too. Someone retiring before becoming eligible for Medicare may use Marketplace coverage for a few years. Someone closer to required distributions may be thinking about future taxable income. The same conversion amount can affect those households differently. [1][2][3][8]
Dovetail Principle: Timing Can Change Which Options Remain
A lower-income year can create room to consider a Roth conversion. The timing only helps when the other income-linked effects remain visible.
Marketplace assistance applies to the coverage year. Medicare may use income from two years earlier. Future retirement income may also change as tax-deferred accounts are used. [3][4][6][8]
That is why the useful question is not only whether to convert. It is what this amount could change if it appears on this year’s return.
What should be reviewed before deciding?
Start with the current income year. Identify the income already expected on the return. Then add the proposed conversion amount. [2][3]
Next, review the income-linked costs that apply to the household:
- Is anyone receiving Marketplace premium tax credits?
- Could this tax year be used for a later Medicare IRMAA determination?
- Would a different conversion amount change either result?
Compare more than one conversion amount. A smaller conversion may still support a retirement tax-planning purpose while producing a different coverage or premium result. [2][4][5][6]
The current tax bill can be estimated. Marketplace income can be updated during the year. Future Medicare premium exposure can be considered before the conversion is completed. These steps cannot guarantee the best outcome, but they can make the tradeoff clearer while choices remain. [3][4][7][8]
A Roth conversion remains a tax decision. In retirement, it may also affect health coverage costs and future Medicare premiums. Before converting, ask: What else could change if this income appears on this year’s return?
Related Reading: Retiring Before Medicare: Coverage and Income Timing. It explains how coverage choices and income decisions can interact before Medicare begins.
About the author
Ross Marino, CFP®, CeFT®, is the Founder & CEO of Dovetail Financial and creator of Human-First Financial Guidance®. He helps people nearing or living in retirement connect their lives and wealth so that financial decisions become clearer, more personal, and easier to navigate.
Notes
- Why Do People Engage In Roth Conversions?. National Tax Journal via IDEAS/RePEc.
- The Arithmetic of Roth Conversions | Financial Planning Association. Financial Planning Association.
- Count income & household size. HealthCare.gov.
- What are premium tax credits and how do they work?. KFF.
- Explaining Health Care Reform: Questions About Health Insurance Subsidies. KFF.
- What is the income-related monthly adjusted amount (IRMAA)?. medicareresources.org.
- 2026 Medicare Parts A & B Premiums and Deductibles. Centers for Medicare & Medicaid Services.
- The 2-Year IRMAA Rule Blindsided You, Spiking Your Medicare Costs. Now What?. Kiplinger. Updated June 30, 2026.
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