Multi-year Roth conversion and IRMAA planning compares conversion schedules across taxes, Medicare premiums, withdrawals, and remaining balances. Test a baseline and alternative schedules using identical household assumptions. A lower current tax bill alone does not establish the better lifetime outcome.
This PureLogicOS guide explains a comparison method, not a recommended conversion amount. Reviewed November 5, 2026. Verify current rules and your personal tax treatment with qualified professionals.
Understand the Roth conversion IRMAA connection
The IRS explains that converting a traditional IRA to a Roth IRA makes previously untaxed amounts taxable. Existing after-tax basis can affect the taxable portion, so do not automatically treat every conversion dollar as taxable in every household.
Social Security explains that Medicare higher-income adjustments depend on modified adjusted gross income. For this purpose, MAGI includes adjusted gross income and tax-exempt interest. For 2026, SSA generally uses tax-year 2024 information. Use the applicable rules and income year for each modeled premium year.
Create a Roth conversion IRMAA baseline and two conversion schedules
| Case | Conversion input | Purpose |
|---|---|---|
| Baseline | No voluntary Roth conversions. | Reference annual taxes, withdrawals, and balances. |
| Even schedule | The same chosen amount in each conversion year. | Inspect a simple repeatable schedule. |
| Variable schedule | Different chosen amounts in specified years. | Inspect timing alongside income, taxes, and premiums. |
Choose test amounts rather than assuming an “optimal” amount. Keep retirement age, spending, investment assumptions, Social Security dates, and filing status consistent unless the purpose is explicitly to test a combined change.
Track the full cash-flow effect
For each year, record the conversion amount, taxable portion, estimated tax, source of cash used to pay that tax, and account balances after the transaction. Distinguish a transfer between retirement account types from money available for household spending. Roth conversion IRMAA planning requires each year’s conversion, tax, and premium to sit in one record.
Add the Medicare premium year associated with the income assumption. A conversion-year tax result and a later premium effect belong in the same evaluation, even though they occur in different years. Where a tool does not model a relevant rule, document the limitation rather than treating the omitted cost as zero.
Review outcomes beyond taxes
Inspect annual after-tax spending coverage, traditional and Roth balances, future withdrawal needs, and the amount available to a surviving household member or heirs. Use consistent assumptions when comparing final balances. Record any assumed tax on a remaining pre-tax balance.
For a household with changing income, identify the years with wages, pension starts, benefit starts, or other significant income. A comparison can show the effects of your assumptions; it cannot establish future law, returns, or individual suitability.
Verify before implementing
A conversion decision should be reviewed against account-specific rules, tax basis records, current brackets, premium rules, and the household’s cash needs. Review actual transactions and filing obligations with your tax professional. Do not execute a conversion solely because a planning estimate appears favorable.
See our Roth conversion software evaluation guide and Income Plan description.
Create a free PureLogicOS Basic account to begin organizing your plan. Projections are educational estimates and do not guarantee tax savings or future outcomes.