Medicare Part D

How IRMAA raises Medicare Part B and D bills in Mount Vernon

MOUNT VERNON, N.Y. — As Medicare's fall Annual Enrollment Period runs through Dec. 7, higher-income retirees in Westchester County are taking a closer look at a line on their Medicare bill that often causes sticker shock: the income-related monthly adjustment amount, or IRMAA. For 2027, the income thresholds that trigger these Part B and Part D surcharges will be published by CMS later this fall, and knowing where you land can help you plan the rest of your year with fewer surprises.

What IRMAA actually is

Most people on Medicare pay the standard Part B premium and whatever premium their Part D drug plan charges. But if your income is above a set level, Medicare adds an extra amount on top. That extra is IRMAA — the Income-Related Monthly Adjustment Amount.

IRMAA is not a penalty for doing something wrong. It's simply a higher share of the program's cost paid by beneficiaries with higher incomes. It applies to Part B (doctor and outpatient coverage) and Part D (prescription drug coverage), whether you get Part D through a stand-alone plan or bundled inside a Medicare Advantage plan.

The 2027 income thresholds

For 2026, IRMAA kicks in when your income is above $109,000 for a single filer or above $218,000 for a married couple filing jointly, according to CMS. From there, the surcharge climbs in tiers — the higher your income, the higher the add-on for both Part B and Part D.

A few important details:

• Medicare looks at your modified adjusted gross income (MAGI) from your tax return two years back. So your 2027 surcharge is based on your 2025 taxes.
• Married couples who file separately have their own, much lower threshold.
• Social Security — not Medicare — is the agency that determines and notifies you about IRMAA.

You'll typically get a letter in the fall or early winter if a surcharge will apply to you next year.

How Mount Vernon retirees usually find out

Mount Vernon is in Westchester County, an area where household incomes can push more retirees over the IRMAA line than in other parts of the country — especially in the year they sell a home, take a large IRA distribution, or convert a traditional IRA to a Roth.

That's why local SHIP counselors often hear the same question: "Why did my Medicare premium jump?" The answer is almost always a one-time income spike two years earlier.

What to do if your income has dropped

If you've had a life-changing event — retirement, reduced work hours, divorce, the death of a spouse, or loss of a pension — you don't have to just accept the surcharge based on old income.

You can file Form SSA-44 with the Social Security Administration to request that they use a more recent (and often lower) income figure. You'll need documentation of the event and your expected income. This is one of the most useful, and most underused, tools in Medicare.

Don't forget the rest of the 2027 Part D picture

IRMAA is just one piece of what you'll pay for drug coverage. For 2027, Part D also has:

• A $2,400 out-of-pocket cap on covered prescriptions in 2027 (up from $2,100 in 2026).
• A maximum deductible of $700 in 2027, up from $615 in 2026(individual plans may set theirs lower).
• Three coverage phases now that the old "donut hole" gap has been eliminated as of 2025.
• The Medicare Prescription Payment Plan, an optional feature that lets you spread your drug costs across the calendar year in monthly installments instead of paying large amounts at the pharmacy counter.

These features apply regardless of whether you owe an IRMAA surcharge.

Key dates to keep in mind

• Annual Enrollment Period: Oct. 15 – Dec. 7, 2026, when you can change Part D or Medicare Advantage coverage for 2027.
• Medicare Advantage Open Enrollment Period: Jan. 1 – March 31, when Medicare Advantage members can make one change.
• IRMAA determinations arrive from Social Security separately from any plan election you make.