04/08/2026
📊 IRMAA stands for Income-Related Monthly Adjustment Amount — a Medicare surcharge added to Part B and Part D premiums for beneficiaries whose income exceeds certain thresholds.
The $1,148 annual figure for Tier 1 combines the Part B surcharge ($81.20/month) and the Part D surcharge ($14.50/month), totaling $95.70/month × 12. These are per-person costs — a married couple where both spouses are on Medicare each pays the surcharge independently.
For married filing jointly, the thresholds are roughly double: $218,000 for Tier 1, $274,000 for Tier 2, up through $410,000 for Tier 4, and $750,000 for Tier 5.
IRMAA is based on Modified Adjusted Gross Income, which includes adjusted gross income plus tax-exempt interest. Municipal bond income counts, even though it is not taxable.
The two-year lookback means income decisions you make today affect Medicare costs two years later. Selling a vacation home, doing a large Roth conversion, or taking an unusually large IRA distribution can all push MAGI over a threshold — and the surcharge applies for the full year.
If income dropped due to a qualifying life event — retirement, death of a spouse, divorce, or reduction in income — Form SSA-44 can be filed with Social Security to request a reduction based on more recent income.
The surcharges shown are above the standard Part B premium of $202.90/month. They are not the total premium — they are the extra amount per tier.