Medicare’s income surcharge looks back two full years, which means a single high-income year (a large capital gain, a Roth conversion) can raise premiums two years later, even if income has since dropped.
How it works
If MAGI from two years ago exceeds the threshold, a Part B and Part D surcharge is added on top of the standard premiums, using rates from the current year’s published bracket table.
What this does not include
IRMAA brackets have multiple tiers with different surcharge amounts — this calculator takes the applicable tier’s surcharge as a direct input rather than the full bracket table, since the specific dollar surcharge depends on exactly which tier MAGI falls into.
How to use this calculator
- Enter MAGI from two years ago and the threshold for your filing status.
- Enter the applicable Part B and Part D surcharge amounts from the current bracket table.
Frequently asked questions
Why does IRMAA use income from two years ago?
Because that’s the most recent tax return data available to Social Security when premiums are set for the coming year — there’s an inherent lag built into the system.
Can IRMAA be appealed?
Yes — for specific life-changing events (retirement, divorce, death of a spouse) that reduced income after the lookback year, a beneficiary can request a new initial determination.
Does a Roth conversion trigger IRMAA?
It can — a large conversion raises MAGI in the conversion year, which can trigger a higher IRMAA tier two years later, a common unintended consequence worth planning around.
