Most Medicare beneficiaries pay the same standard premium for Part B and Part D coverage. But above certain income levels, Medicare adds a surcharge known as IRMAA—the Income-Related Monthly Adjustment Amount. For 2026, those thresholds have been updated, and the amounts involved are significant enough that every higher-income retiree should know where they stand.
The Two-Year Lookback
IRMAA is calculated using your Modified Adjusted Gross Income (MAGI) from two years prior. Your 2026 Medicare premiums are based on income you reported on your 2024 tax return—the one you filed in 2025. That lag matters enormously. If you had an unusually high-income year in 2024—a large Roth conversion, the sale of a home or business, a required minimum distribution on top of normal income—you may find yourself paying a substantially higher Medicare premium in 2026 even if your income has since dropped.
The 2026 IRMAA Thresholds
For 2026, CMS raised the first IRMAA threshold from $106,000 (for single filers) in 2025 to $109,000. For married couples filing jointly, the threshold moves from $212,000 to $218,000. This means that if your 2024 MAGI fell below these levels, you pay only the standard premium.
Above those thresholds, the surcharges are layered across five brackets. The standard 2026 Part B premium is $185.00 per month, and the IRMAA brackets build on that:
For a single filer with 2024 MAGI between $109,000 and $137,000 (or married filing jointly between $218,000 and $274,000), the total Part B premium rises to a meaningfully higher amount. The surcharges continue to climb through additional brackets up to $500,000 for single filers, where the maximum premium applies. Part D coverage carries separate, stacked IRMAA surcharges as well—a married couple in the highest bracket can owe over $600 per month in combined Part B and Part D surcharges alone.
Why This Catches Retirees Off Guard
IRMAA surprises retirees for a predictable reason: the income that triggers it often comes from one-time events that felt like good financial management at the time. Roth conversions, which reduce future required minimum distributions and can lower lifetime taxes, generate taxable income in the year of conversion. Selling a second home or an investment property can push income well above the first bracket in a single year.
The problem compounds when retirees don't anticipate the two-year delay. Someone who converts a large IRA in 2024 may not think about the IRMAA consequences until they receive their Medicare premium notice in late 2025—at which point options are limited.
You Can Appeal a Life Change
If your income has dropped significantly since your base year because of a qualifying life-changing event—retirement, divorce, death of a spouse, or reduction of work hours—you can appeal your IRMAA determination using Form SSA-44. Medicare will then use a more recent tax year to calculate your surcharge. This appeal is worth pursuing for anyone whose circumstances have genuinely changed.
Planning Ahead
The gap between when income is earned and when it affects Medicare premiums creates both a risk and an opportunity. Retirees who understand the IRMAA brackets can manage income with an eye toward keeping MAGI in a specific range. Timing Roth conversions, managing capital gains, and coordinating qualified charitable distributions from IRAs are all tools that a financial planner familiar with Medicare premiums can use to reduce or avoid surcharges.
The bracket thresholds are not indexed at a rate that keeps pace with portfolio growth, so more retirees cross into IRMAA territory each year. Checking your projected income before year-end—when adjustments are still possible—is one of the more valuable exercises in retirement tax planning.