Most Medicare enrollees pay $202.90 a month for Part B in 2026. But a retiree whose 2024 income crossed $109,000 pays $284.10 for exactly the same coverage, and at the top of the scale the bill runs $689.90 a month. The difference is IRMAA, the income-related monthly adjustment amount, and it surprises more new retirees than almost any other feature of Medicare.
IRMAA is not a penalty and not a different insurance product. It is a surcharge, set in law, that higher-income beneficiaries pay on top of the standard Part B and Part D premiums. Here is how the 2026 numbers work, why the government is looking at your income from two years ago, and the appeal that can erase the surcharge when your income has dropped.
The 2026 numbers
The Centers for Medicare and Medicaid Services set the 2026 standard Part B premium at $202.90 a month, up $17.90 from 2025, with an annual deductible of $283, in its fact sheet on 2026 Part A and B costs. The same announcement sets the IRMAA tiers, which add between $81.20 and $487.00 a month to Part B for roughly the highest-earning 8 percent of enrollees.
For a single filer, the surcharge begins once modified adjusted gross income tops $109,000; for a couple filing jointly, $218,000. From there the Part B bill steps up through five tiers, reaching $649.30 a month for singles above $205,000 and topping out at $689.90 a month above $500,000 (above $750,000 for joint filers). People enrolled in Part D drug coverage pay a parallel income-based amount on top of their plan’s premium, billed by Medicare rather than the plan.
Why they look at your income from two years ago
Your 2026 surcharge is based on your 2024 tax return, the most recent one the IRS had fully processed when Social Security ran its determination. The Social Security Administration explains the mechanics in its guide, Medicare Premiums: Rules for Higher-Income Beneficiaries. The income measure is modified adjusted gross income: your adjusted gross income plus tax-exempt interest, which means municipal bond income counts even though it escapes federal tax.
The two-year lookback is what trips up new retirees. A strong final year of salary, a large Roth conversion, a home sale with a taxable gain, or a big IRA withdrawal in 2024 can push your 2026 premium up even if you are living on far less today. If you receive Social Security, the surcharge is deducted from your monthly benefit; otherwise Medicare bills you directly.
The brackets are cliffs, not ramps
IRMAA has no phase-in. One dollar of extra income over a threshold moves you into the next tier for the entire year. A single filer with $109,000 of 2024 MAGI pays the standard $202.90 in 2026; a neighbor who reported $109,001 pays $284.10 every month, roughly $974 more over the year, because of that single dollar.
That cliff structure is why financial planners watch the thresholds when timing Roth conversions, capital gains, and large retirement withdrawals. The brackets are adjusted for inflation annually, so each fall’s announcement resets the lines. Married people who file separately face the harshest schedule: most of them skip directly to the upper tiers once income passes the first threshold.
When you can appeal: the life-changing event rules
Social Security will recalculate your IRMAA using a more recent year if your income fell because of a life-changing event on its official list: marriage, divorce or annulment, death of a spouse, stopping or reducing work, losing income-producing property through no fault of your own, losing or seeing a cut in a pension, or receiving an employer settlement from a bankruptcy or reorganization.
Retirement itself is the most common trigger. If you stopped working in 2025 or 2026 and your income is now well below what your 2024 return showed, file Form SSA-44, Medicare Income-Related Monthly Adjustment Amount, Life-Changing Event, with evidence of the event and an estimate of your new income. Approved requests apply to the current year, not just future ones, and overpaid surcharges are credited back.
Note what is not on the list: a bad year in the stock market, a one-time capital gain you chose to take, or a large Roth conversion. Those simply ride through the system, and the surcharge drops off on its own two years later when the lookback rolls forward.
If you think the number is simply wrong
Separate from the life-changing event process, you can ask Social Security to correct its records if it used the wrong tax return, if the IRS data was outdated because you filed an amended return, or if a more recent return is available. Call Social Security or bring a copy of the corrected return to a field office. You also have formal appeal rights, starting with a reconsideration request, and the determination letter you receive each fall explains the deadline.
The practical takeaway: read the IRMAA notice when it arrives rather than filing it away. The surcharge is real money, up to about $5,800 a year per person at the top Part B tier, but the two most common situations, a recent retirement or an outdated tax return, are exactly the ones the appeal process was built to fix.
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