Medicare Part D

How Income Shapes Your 2026 Medicare Part B and D Costs

SCOTTSDALE, Ariz. — As Medicare's Annual Enrollment Period runs through Dec. 7, higher-income retirees here are getting a fresh look at something that surprises a lot of people every fall: the amount you pay for Part B and Part D isn't just about the plan you pick. It's also about what you earned two years ago.

For 2026, the income-related monthly adjustment amount — better known as IRMAA — kicks in above $109,000 in yearly income for a single filer, based on your 2024 tax return. If that's you, your Part B premium and your Part D premium will both include an extra surcharge. Here's what that actually means, and what to do about it before the Dec. 7 deadline.

What IRMAA is, in plain English

IRMAA is an extra amount added to your standard Medicare Part B and Part D premiums when your income is above a certain level. It's not a penalty for doing anything wrong — it's a sliding scale Congress built into Medicare so higher earners pay a larger share.

Two important things to know:

• Social Security uses your tax return from two years ago. For 2027, that means your 2025 IRS filing.
• IRMAA applies to both Part B and Part D. The Part D surcharge is paid on top of whatever your drug plan charges — and yes, it applies even if you're in a Medicare Advantage plan that includes drug coverage.

The income thresholds for 2027

For a single filer in 2026, IRMAA starts once your modified adjusted gross income (MAGI) is above $109,000. Married couples filing jointly cross the first threshold at a higher combined income. From there, the surcharge grows in tiers — the more you earn, the larger the add-on for both Part B and Part D.

Medicare.gov publishes the full tier chart each year, and it's worth reading closely if your income is anywhere near a threshold. Even a few hundred dollars over a bracket line can move you into the next tier.

Why this matters this fall

The Annual Enrollment Period (Oct. 15 – Dec. 7, 2026) is when most people can change their Part D drug plan or their Medicare Advantage plan for 2027. IRMAA itself isn't something you "enroll in" — Social Security calculates it automatically — but the plan you pick during AEP determines the base Part D premium your surcharge gets added to. CMS typically publishes the 2027 Part B figures and IRMAA brackets later in the fall.

A few other numbers worth knowing while you're comparing:

• Part D out-of-pocket cap: $2,100 in 2026 and $2,400 in 2027. Once your covered drug spending hits that cap, you pay nothing more for covered drugs the rest of the year.
• Part D maximum deductible: $615 in 2026 and $700 in 2027.
• The old "donut hole" is gone as of 2025. Part D now has three phases: deductible, initial coverage, and catastrophic.
• Medicare Prescription Payment Plan lets you spread your drug costs into monthly payments instead of paying a big bill at the pharmacy counter.

If your income has dropped, you can appeal

This is the part a lot of Scottsdale readers miss. If a "life-changing event" has lowered your income since 2025 — retirement, the death of a spouse, divorce, loss of pension income, or a work reduction — you can ask Social Security to recalculate your IRMAA using more recent income.

The form is SSA-44, available at ssa.gov. You'll need documentation of the event and your newer income. If approved, your surcharge is adjusted going forward.

What Scottsdale readers should do before Dec. 7

Scottsdale is in Maricopa County, where the CMS Landscape lists 79 Medicare Advantage plans from 16 carriers for 2027, down from 88 plans (also 16 carriers) in 2026. Of those, 62 plans continue, 17 are new, 13 are not returning, and 13 have been renamed; 20 continuing plans change something in their terms, with the specifics in each plan's Annual Notice of Change. Availability is set at the county level, so two neighbors on opposite sides of Scottsdale see the same menu.

A practical checklist:

1. Pull your 2024 tax return and see where your MAGI landed compared to the $109,000 single-filer threshold. 2. Check your Social Security "Initial IRMAA Determination" letter if you received one — it explains the tier they placed you in. 3. Use the Plan Finder at medicare.gov to compare Part D or Medicare Advantage options based on your actual prescriptions. 4. Don't forget the Medicare Advantage Open Enrollment Period (Jan. 1 – March 31) if you're already in an MA plan and want a do-over.