How IRMAA and the Two-Year Look-Back Can Raise Your 2026 Medicare Part B Premium

The Basics: What You Pay for Part B in 2026

Medicare Part B covers doctor visits, outpatient care, lab work, and many preventive services. Most people pay a standard monthly premium for this coverage, and for 2026 that standard amount is $202.90 per month. That figure applies to the large majority of enrollees.

But Medicare premiums are not one-size-fits-all. Higher-income retirees can pay a good deal more because of a rule called the income-related monthly adjustment amount, usually shortened to IRMAA. Understanding how IRMAA is calculated, and when it kicks in, can prevent an unwelcome surprise in your monthly Social Security statement or bank draft.

What IRMAA Actually Is

IRMAA is a surcharge added on top of the standard Part B premium (and, separately, on top of your Part D prescription drug premium) when your income rises above certain thresholds. It is not a penalty for doing anything wrong. It is simply a sliding scale: the more income you report, the higher your monthly premium climbs.

For 2026, according to the Centers for Medicare and Medicaid Services (CMS), the first IRMAA threshold begins at $109,000 for single filers and $218,000 for married couples filing jointly. If your income stays at or below those numbers, you pay only the standard $202.90 premium. Cross the line, even by a dollar, and you move into a higher bracket that adds a surcharge to what you owe.

The income figure Medicare uses is your modified adjusted gross income, or MAGI. In simple terms, that is your adjusted gross income plus certain items such as tax-exempt interest. It is a broader measure than the taxable income you might focus on at tax time, which is one reason people are sometimes caught off guard.

The Two-Year Look-Back: The Detail That Trips People Up

Here is the part of IRMAA that causes the most confusion. Medicare does not look at your current income to set your premium. It looks back two years.

That means your 2026 Part B premium is based on the income reported on your 2024 tax return. Medicare works from the most recent return the IRS has on file, which is typically two years old.

This lag matters enormously for retirees, because retirement is often exactly the moment when income drops sharply. You may have stopped working, but Medicare is still looking at a year when you were earning a full salary. The result can be a surcharge that reflects a financial reality you no longer live in.

The look-back is especially important for anyone who had a one-time spike in income two years earlier. Consider a few common examples:

• §Selling a business or a rental property, which can produce a large capital gain in a single year.
• §Completing a large Roth conversion, which adds the converted amount to your taxable income.
• §Receiving an inheritance that generated taxable income, or selling inherited assets.

Any of these can push your MAGI above the IRMAA threshold for that one year. Because of the two-year lag, the higher premium shows up later, even though the money is long gone and your income has since returned to normal.

How the Surcharge Is Structured

IRMAA is tiered. Rather than a smooth increase, income is divided into brackets, and each bracket carries a specific surcharge amount added to the standard premium. Moving from one bracket to the next raises your premium by a set dollar amount, not a percentage.

Because the brackets are cliffs rather than gradual slopes, being just over a threshold costs the same as being well into that bracket. This is why the exact dollar figure of your MAGI can matter so much. A small difference in reported income can occasionally be the difference between two premium levels.

The same income figure that triggers a Part B surcharge also triggers a Part D surcharge, so the effect can compound across both parts of your coverage.

When Your Income Has Dropped: The Life-Changing Event Review

The two-year look-back would be unfair if there were no way to account for a genuine change in circumstances, so Medicare provides one. If your income has fallen because of a qualifying life event, you can ask Medicare to use more recent income instead of the two-year-old return.

This process is a life-changing event appeal. Qualifying events generally include:

• §Retirement or a reduction in work hours that lowers your earnings.
• §The death of a spouse.
• §Divorce or annulment.
• §Loss of income-producing property.
• §Loss or reduction of a pension.

To request the review, you complete the appropriate Social Security form, describe the event, and provide documentation such as a letter from a former employer or proof of the change. If approved, Medicare recalculates your premium based on your reduced income rather than the higher figure from two years ago.

Why This Is Worth Understanding in Advance

The key takeaway is that income decisions made today can echo into your Medicare premiums two years from now. A large Roth conversion or a property sale may make sense for other reasons, but it helps to know that the same transaction could raise your Part B and Part D costs for a year down the road.

Equally important, if your income has already dropped because of retirement or another major life change, you are not necessarily stuck paying a surcharge based on outdated numbers. The life-changing event review exists precisely for that situation.