Medicare Part D

How IRMAA Adjusts Medicare Part B and D Costs in Charleston

CHARLESTON, S.C. — If you've watched your income tick up in retirement — maybe from a Roth conversion, a home sale, or a strong year of investments — there's a Medicare rule worth knowing before the new plan year starts. It's called IRMAA, short for the Income-Related Monthly Adjustment Amount, and it decides whether higher earners pay extra for Medicare Part B and Part D in 2027.

Here's a plain-English look at how it works, the income thresholds that trigger it, and what Charleston-area readers can do if a surcharge shows up in the mail.

What IRMAA actually is

IRMAA isn't a separate bill or a penalty. It's an add-on to your regular Part B premium and, if you have drug coverage, your Part D premium. Social Security calculates it automatically based on the income you reported to the IRS two years earlier. So your 2027 IRMAA is based on your 2025 tax return.

Most people with Medicare don't pay IRMAA. It only kicks in above certain income levels — and if you're under those levels, you'll pay the standard Part B premium and whatever your Part D plan charges.

The 2027 income thresholds

For 2026, IRMAA starts when your modified adjusted gross income (MAGI) is above $109,000 for a single filer or $218,000 for a married couple filing jointly, based on your 2024 return.

Above those first thresholds, the surcharge rises in tiers. The higher your income, the higher the add-on — both for Part B and for Part D. There are five tiers in total, with the top tier applying to single filers with income above roughly $500,000 (and married couples above roughly $750,000). CMS publishes the exact 2026 dollar amounts for each tier on Medicare.gov each fall.

A few points worth remembering:

• The brackets are cliffs, not gradual. One dollar over a threshold moves you into the next tier for the whole year.
• IRMAA is recalculated every year, so a one-time income spike in 2025 may not follow you forever.
• Part D IRMAA is added to whatever premium your drug plan already charges — it doesn't replace it.

How you'll find out

If you owe IRMAA in 2027, Social Security will send you a predetermination notice, usually late in 2026. The Part B portion is deducted from your Social Security check (or billed directly if you're not yet collecting). The Part D portion is billed separately by Medicare — not by your drug plan — even though it's tied to the plan you're enrolled in.

That surprise Part D bill trips up a lot of first-time IRMAA payers. It's a real Medicare charge; don't ignore it.

Life changes can lower or erase it

Because IRMAA looks back two years, it can feel unfair when your current income is much lower — say, you've since retired, lost a spouse, or stopped working part-time. Social Security allows you to request a new decision after certain life-changing events, including:

• Marriage, divorce, or the death of a spouse
• Work stoppage or reduction
• Loss of pension income
• Loss of income-producing property from a disaster or event beyond your control

You file Form SSA-44 with documentation. If approved, Social Security will use your more recent (or expected) income instead. This is one of the most useful — and most overlooked — tools in the Medicare rulebook.

You can also appeal an IRMAA determination if you believe the IRS data used was wrong or outdated.

What this means locally

Charleston is in Charleston County, where Medicare beneficiaries choose each fall between staying with Original Medicare (often paired with a standalone Part D plan) and enrolling in a Medicare Advantage plan that includes drug coverage. IRMAA applies the same way in either path: if your income clears the threshold, you'll owe the Part B surcharge, and — if you have any form of Part D coverage — the Part D surcharge too.

The Annual Enrollment Period runs October 15 through December 7, with a Medicare Advantage Open Enrollment window from January 1 through March 31 for people already in an Advantage plan. Those windows are the right time to review your coverage; they don't change IRMAA itself, but they're a good moment to make sure your overall Medicare picture — premium, drug coverage, and any surcharge — still fits.

Also worth noting for 2027: the annual out-of-pocket cap on Part D drug costs is $2,400, and the maximum Part D deductible is $700. The coverage gap (the old "donut hole") has been eliminated. And the Medicare Prescription Payment Plan lets you spread your drug costs across the year in monthly installments if you'd prefer smoother billing.

Quick FAQ

Does IRMAA ever go away on its own? Yes. Each year Social Security pulls a fresh tax return. If your income drops below the threshold, the surcharge goes away the following year — no appeal needed.

Do Roth conversions count toward IRMAA? Yes. Roth conversions add to your MAGI in the year you convert, which can push you over a bracket two years later. Many retirees plan conversions carefully with this in mind.

I just retired. Do I have to pay IRMAA based on my old salary? Not necessarily. "Work stoppage" is a qualifying life-changing event. File Form SSA-44 with proof, and Social Security can use your reduced income instead.

Is IRMAA the same for everyone in the same bracket? Yes. IRMAA is set by the federal government, not by your plan or your ZIP code. Two Charleston neighbors in the same income tier pay the same surcharge.

Where to get answers you can trust

The 2027 IRMAA dollar amounts and thresholds are published by CMS later in the fall, usually in November. For the official figures, go straight to the source: Medicare.gov (search "Part B costs" and "Part D costs"). You can also call 1-800-MEDICARE (1-800-633-4227), 24 hours a day, seven days a week.

For free, unbiased, one-on-one help in South Carolina, contact SHIP — the State Health Insurance Assistance Program, known locally as South Carolina SHIINE. Counselors don't sell anything and can walk you through IRMAA notices, appeals, and Form SSA-44 at no cost.

For IRMAA appeals or life-change requests specifically, contact the Social Security Administration at 1-800-772-1213 or visit ssa.gov.