Roth Conversion and IRMAA — Your 2026 Conversion Sets Your 2028 Premium
A Roth conversion counts as income, and Medicare sets your premium from the return you filed two years earlier. So a conversion made this autumn surfaces as a surcharge two Januarys later. Enter your income and the amount you are weighing to see which thresholds it crosses and what each step costs.
Works offline — your inputs never leave this device. How that works
You are just over the last threshold
Your income lands $21,000 past $109,000. That final stretch is what costs $1,148 for the year. Converting $21,000 less would land you on the cheaper side of that edge. Whether that is worth doing depends on the tax you would save by converting, which this page does not calculate.| Income | Extra per year |
|---|---|
| $109,000 or less | Nothing extra |
| $109,000 – $137,000(you) | $1,148 |
| $137,000 – $171,000 | $2,885 |
| $171,000 – $205,000 | $4,620 |
| $205,000 – $500,000 | $6,355 |
| Above $500,000 | $6,936 |
You are $7,000 below the next step. Going one dollar over it would add $1,736 for the year — not a little more, the whole step.
This is the Medicare surcharge only — not the cost of converting
A conversion has two costs. The first is the income tax you owe on the amount converted, in the year you convert it, and that is nearly always the larger of the two. This page does not calculate it, because doing it properly takes your brackets, your deductions, your state, how the conversion stacks with capital gains, and how much of your Social Security it makes taxable.
The second cost is the one shown above: the Medicare surcharge that arrives two years later, which people are far less likely to have counted. Put the two together with someone who can see your whole return — that is a question for a CPA or a fee-only planner, and this page lists what each of them costs.
Which bracket table these figures use
A conversion made in 2026 sets your 2028 premium, and CMS will not publish 2028 brackets until the autumn of 2027. We do not invent them. The figures above use the verified 2026 table, checked against the CMS notice that set it.
The thresholds move with inflation each year, so the real 2028 edges will sit higher than the ones shown. That tells you which way this estimate is wrong: your actual room before a threshold will be at least what is shown here, and the surcharge at a given income at most. Treat it as the shape of the staircase rather than as a determination — only Social Security sets a surcharge.
If the surcharge arrives and your income has since fallen
Form SSA-44 asks Social Security to use a more recent year, but only after one of eight life-changing events — retirement, reduced hours, divorce, the death of a spouse, a pension ending. A conversion you chose to make is not one of them, which is the reason to look at this before rather than after. See the eight events.Where to take a plan question
We take no money from any insurer and name none, so we are not the place to settle what you buy. These three are, and all of them are free.
Verified 2026-08-02 against CMS fact sheet, "2026 Medicare Parts A & B Premiums and Deductibles / 2026 Medicare Part D Income-Related Monthly Adjustment Amounts" (November 14, 2025); the same tables appear in CMS-8091-N, 90 FR 52063 (November 19, 2025) and on Form SSA-44 (12-2025) (effective 2026-01-01)
Estimate only — not financial, tax, legal, or insurance advice. Only CMS can determine your actual amounts.
Official source: CMS — 2026 Medicare Parts A & B premiums and deductibles ↗
🎓 Understand this tool
What it is
A Roth conversion counts as ordinary income in the year you make it, and Medicare sets each year's premium from the tax return filed two years earlier. This tool takes your income for the year and the amount you are weighing, and shows which published IRMAA thresholds the sum crosses, what each of those steps costs for twelve months, and how much room is left before the next one.
How it works
It adds the conversion to the income you enter, looks both figures up in the verified CMS bracket table, and reports the difference. Nothing is modelled or projected: the surcharge at each tier is the exact dollar amount CMS published. Because the table that will govern the premium year has not been published yet — a 2026 conversion sets the 2028 premium — the current verified table stands in for it, and the page says so beside the result.
Getting the most from it
- Enter what your income for this year will be WITHOUT the conversion: adjusted gross income plus tax-exempt interest, the same definition Medicare uses.
- Enter the amount you are considering converting. All of it counts as income in the year you convert it, whatever you do with the money afterwards.
- Set your filing status. Married filing separately has only three published rows, so its first step is far larger than the equivalent step for the other two statuses.
- If both of you are on Medicare, turn on the household setting: one conversion, one joint income, and the surcharge billed to each of you separately.
- Read the two figures that matter — what the conversion adds to your Medicare cost, and how far past the last threshold your income landed. The second one is usually the cheaper to change.
Reading your result
The headline number is what this conversion adds to your Medicare premiums for one year, two years from now. If the result says you are a small amount past a threshold, that is the finding worth acting on: IRMAA is a cliff, so the last few hundred dollars of a conversion can carry the entire cost of a step. Treat every figure as an estimate of what the published tables produce, not as a determination — only Social Security sets a surcharge.
What it can't tell you
It does not calculate the income tax on the conversion, which is nearly always the larger cost and needs your brackets, deductions, state tax, capital-gains stacking and the effect on the taxation of your Social Security. It therefore cannot tell you whether converting is worth it, and it does not try: that is a question for a CPA or a fee-only planner. It also cannot know next year's thresholds, and Form SSA-44 will not undo a surcharge caused by a conversion you chose to make — the eight life-changing events do not include one.
Frequently asked questions
It can, because the converted amount counts as income in the year you convert, and Medicare sets each year's premium from the tax return filed two years earlier. A conversion in 2026 is measured for your 2028 premium. Whether it raises anything depends entirely on whether the extra income carries you past a published threshold.
Related calculators
IRMAA Calculator
IRMAA is the income-related surcharge added to your Medicare Part B and Part D premiums when the tax return you filed two years ago showed income above a threshold. Enter that income and your filing status to estimate your tier, the monthly and yearly surcharge, and exactly how many dollars sit between you and the next cliff.
Taxes on benefits
Work out how much of your Social Security is taxable, using the combined-income test the IRS actually applies: your other income, plus any tax-exempt interest, plus half your benefits. Crossing a threshold taxes only the amount above it, up to 85%, which makes it a bracket rather than the cliff Medicare's income surcharge uses. Estimate only.
SSA-44 Walkthrough
Form SSA-44 is how you ask Social Security to base your Medicare surcharge on this year's income instead of the two-year-old tax return that triggered it. Here are the eight life-changing events that qualify, the evidence Social Security accepts for each one, and how the form is filed. Filing it is free.
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