Enter the taxable amount, not just the transfer
A traditional IRA conversion is generally included in gross income to the extent the converted distribution would otherwise be taxable. Nondeductible basis can make the taxable amount different from the amount moved. Form 8606 and the IRA aggregation rules may be relevant, so this calculator asks for the taxable amount expected to reach MAGI.
The lookback creates a timing gap
A conversion completed in 2026 generally appears on that year's return and can affect 2028 Medicare premiums. Official 2028 IRMAA thresholds and premium amounts are not yet published. The calculator therefore applies the conversion to the published 2026 table as a reference scenario; it does not label that result as a 2028 premium forecast.
The cost comparison includes changes to both Part B and the separate Part D income-related adjustment. It excludes the beneficiary's Part D plan premium, which varies by plan.
Use the added annual Medicare cost to understand tier sensitivity, not as a promise of future cost. Future thresholds, standard premiums, and income-related adjustments can all change.
Coordinate the full tax picture
A conversion can also change federal and state income tax, taxable Social Security benefits, net investment income tax, credits, deductions, and other income-based rules. Compare those effects with future RMDs and estate goals. A tax professional can model the filed-return details that this focused tool does not collect.
Last reviewed August 16, 2026. Calculations use the CMS source of record.