Medicare Part D

How IRMAA works in 2027: the income brackets that add to your Medicare bill

NORRISTOWN, Pa. — If you are on Medicare and your income has climbed in recent years, you may see a higher premium bill in 2027 than your neighbor pays. That extra charge has a name: IRMAA, short for the Income-Related Monthly Adjustment Amount. It is not a penalty and it is not permanent — it is a surcharge tied to what your tax return showed two years ago. With the Annual Enrollment Period running from Oct. 15 to Dec. 7, this is a good time to understand how the brackets work and what to do if the number on your Social Security letter looks wrong.

What IRMAA actually is

Most people on Medicare pay the standard Part B premium and, if they have drug coverage, a Part D premium set by their plan. IRMAA is an extra amount added on top of both of those if your income is above certain thresholds. The Part B surcharge is billed by Medicare (usually pulled from your Social Security check). The Part D surcharge is also billed by Medicare directly — not by your drug plan — even though the base Part D premium goes to the insurer.

The key point: IRMAA is not a different plan or a different level of coverage. It is the same Medicare, just at a higher monthly cost for higher-income households.

The 2027 income brackets

For 2027, IRMAA begins once your modified adjusted gross income (MAGI) from your 2025 tax return crosses these lines. CMS publishes the exact 2027 bracket dollars later this fall, alongside the Part B figures.

• Single filers: surcharges start above $109,000.
• Married filing jointly: surcharges start above $218,000.
• Married filing separately: a separate, tighter schedule applies and surcharges begin at a much lower income.

From there, the surcharge climbs in tiers. There are five IRMAA brackets in total, and the top tier applies to single filers with income at or above $500,000 (and married couples at or above $750,000). Each bracket adds a set dollar amount to both your Part B and your Part D premium.

The exact dollar amounts for each tier are posted on Medicare.gov once finalized for the year. Because the base Part B premium and the Part D national base beneficiary premium can shift year to year, the surcharge dollars shift with them.

Why the IRS number matters — and which year

Social Security uses your most recent tax return on file, which usually means income from two years earlier. So your 2027 IRMAA is based on your 2025 tax return. That two-year lag catches a lot of people off guard, especially in the first year or two of retirement, when a working year is still driving the calculation.

MAGI for IRMAA purposes is your adjusted gross income plus any tax-exempt interest. That means municipal bond interest counts, even though it does not show up as taxable income.

What to do if your income has dropped

This is the piece many people miss. If you had a "life-changing event" that reduced your income after the tax year Social Security is using, you can ask them to use more recent figures. Qualifying events include:

• Retirement or reduced work hours
• Marriage, divorce, or the death of a spouse
• Loss of a pension
• Loss of income-producing property (not from a normal market drop)

The form is SSA-44, "Medicare Income-Related Monthly Adjustment Amount – Life-Changing Event." You submit it to Social Security with proof (a letter from a former employer, a death certificate, a signed estimate of the current year's income). If approved, they recalculate your IRMAA using the newer number.

If you simply disagree with how Social Security read your tax return, you can file a standard reconsideration request instead.

How this connects to your Norristown coverage choices

Norristown is in Montgomery County, where residents choose each fall between Original Medicare (often paired with a Medigap policy and a stand-alone Part D plan) and Medicare Advantage. IRMAA applies the same way in both paths — it is tied to your income, not to which type of coverage you pick. Switching from Advantage to Original Medicare will not remove an IRMAA surcharge, and vice versa.

What can change year to year is your Part D plan, and that matters because the Part D IRMAA is added to whatever base premium your drug plan charges. During the Annual Enrollment Period (Oct. 15 – Dec. 7), it is worth reviewing your drug coverage regardless of your income bracket — especially with the Part D annual out-of-pocket cap moving from $2,100 in 2026 to $2,400 in 2027.

A few common mistakes to avoid

• Assuming the letter is final. The Social Security notice you get in late fall tells you what your 2027 premium will be. If a life event applies, act on it — do not just pay the higher amount all year.
• Forgetting Roth conversions and capital gains count. A one-time bump from selling a house or converting a traditional IRA to a Roth can push you into an IRMAA tier two years later. Planning the timing matters.
• Missing that it resets. IRMAA is recalculated every year with fresh tax data. If your 2026 income comes back down, your 2028 premium likely will too.