How IRMAA Is Calculated After a Filing Status Change
Why does IRMAA change after my filing status changes?
Medicare IRMAA is based on both Modified Adjusted Gross Income (MAGI) and tax filing status.
The income thresholds for a single filer are lower than the thresholds for Married Filing Jointly. As a result, a surviving spouse may be subject to IRMAA at a lower household income after changing to Single filing status.
IRMAA also generally uses income from two years prior to determine the current year’s Medicare premium. For example, 2026 IRMAA is generally based on 2024 MAGI.
Because of this two-year lookback, a plan may show higher IRMAA costs for a period after income or filing status changes. The IRMAA calculation will continue to reflect the applicable prior-year MAGI and filing status used for each Medicare premium year.
The death of a spouse is also considered a qualifying life-changing event for Medicare IRMAA purposes. In real life, a beneficiary may be able to request that Social Security use more recent income information if the death results in a significant reduction in income.