A high-income year can come with an unexpected Medicare sequel. Earn more today, and Medicare may use that income later to decide that future Part B and Part D premiums should cost more.
That system goes by a wonderfully bureaucratic name: the Income-Related Monthly Adjustment Amount, or IRMAA. The good news is that the rules make more sense once the numbers are separated from the alphabet soup, and the 2026 figures show exactly how much a high-income household can add to its monthly Medicare bill.
1. The first Part B surcharge: $81.20
For 2026, Medicare charges most people a standard Part B premium of $202.90 per month, but higher-income beneficiaries can pay an additional IRMAA. For an individual tax filer, the first IRMAA tier applies when 2024 modified adjusted gross income exceeded $109,000 but did not exceed $137,000. And for married couples filing jointly, that first range runs above $218,000 through $274,000.
The Part B IRMAA at this first level adds $81.20 per month, bringing the total Part B premium to $284.10. That works out to an extra $974.40 over a full year, assuming the surcharge applies for all 12 months. The important detail hides in the calendar: Medicare generally looks two years back, so 2026 premiums generally rely on 2024 tax information.
2. The second Part B surcharge: $202.90
The next income tier packs a much bigger punch. In 2026, an individual with 2024 MAGI above $137,000 through $171,000, or a married couple filing jointly above $274,000 through $342,000, faces a $202.90 monthly Part B IRMAA.
That surcharge equals the entire standard Part B premium, so the monthly Part B bill reaches $405.80. A one-time event such as selling a large investment position can therefore have consequences long after the money lands in the bank. This creates one of the most common retirement-planning surprises: a profitable year can feel great at tax time and considerably less charming when the Medicare bill arrives later.
3. The third Part B surcharge: $324.60
The third Part B tier starts above $171,000 and reaches $205,000 for individual filers, while married couples filing jointly enter the range above $342,000 through $410,000. At that level, the 2026 Part B IRMAA adds $324.60 every month.
That pushes the total Part B premium to $527.50 a month. The surcharge does not depend simply on salary, either, because Medicare uses modified adjusted gross income from the applicable federal tax return. MAGI for IRMAA purposes incorporates adjusted gross income plus certain tax-exempt income, which means tax-free interest can matter even when it does not show up as taxable income.
4. The fourth Part B surcharge: $446.30
The fourth tier applies when 2024 MAGI exceeds $205,000 but remains below $500,000 for an individual, or exceeds $410,000 but remains below $750,000 for a married couple filing jointly. The 2026 Part B IRMAA at this level reaches $446.30 per month.
Add that surcharge to the $202.90 standard premium and the monthly Part B cost becomes $649.20. A retirement portfolio sale, business transaction, unusually large bonus, or other taxable income event can push a household into this range even when its ordinary annual income usually sits much lower. That timing explains why retirement planning should consider Medicare premiums before making large taxable-income moves, rather than treating IRMAA as a problem to solve after the fact.
5. The fifth Part B surcharge: $487
At the top of the 2026 Part B scale, individual filers with MAGI of $500,000 or more and married couples filing jointly with MAGI of $750,000 or more pay a $487 monthly IRMAA. That produces a total Part B premium of $689.90 per month.
The married-filing-separately rules can look especially startling because they use a different table when spouses lived together during the tax year. In 2026, that filing status can trigger the $446.30 Part B adjustment above $109,000 through below $391,000, followed by the $487 adjustment at $391,000 or more. Filing status therefore matters just as much as the income number itself when Medicare calculates IRMAA.
6. Part D gets its own surcharge
Part B does not get all the IRMAA attention because Medicare also adds an income-related adjustment to Part D prescription drug coverage. In 2026, the five Part D IRMAA amounts range from $14.50 to $91.00 per month, and the amount comes on top of the premium charged by the person’s drug plan.
For example, an individual with 2024 MAGI above $109,000 through $137,000 pays $14.50 extra each month, while someone at $500,000 or more pays $91.00 extra; married couples filing jointly use higher income thresholds, topping out at $750,000 for the highest tier. The surcharge also applies when Part D coverage comes through a Medicare Advantage plan that includes prescription drug coverage.
The Medicare Bill Can Have a Two-Year Memory
The most important point may be the simplest one: a high-income year does not necessarily raise Medicare premiums immediately. For 2026, Medicare generally looks at 2024 MAGI, so an income spike can show up in premiums later, after the original financial event has faded from memory.
There is also a safety valve for certain major life changes. If income later falls because of qualifying events such as retirement or reduced work, marriage, divorce, the death of a spouse, certain losses of income-producing property, loss of pension income, or an employer settlement, a beneficiary can ask Social Security to reconsider the IRMAA amount.
The smart move after a high-income year is not panic, but planning. Check the tax return Medicare will use, watch the IRMAA thresholds, and pay attention to the timing of large taxable transactions. Medicare may have a long memory, but a careful retirement plan can account for it.
What other Medicare costs or retirement surprises would you like to see explained next?
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