Medicare Part D

How Part B and Part D late penalties work in St Louis Medicare

ST. LOUIS — Some Medicare mistakes get fixed with a phone call. Others follow you the rest of your life.

That's the hard truth about late-enrollment penalties for Part B (doctor visits and outpatient care) and Part D (prescription drugs). Sign up late without a good reason, and Medicare can add a permanent charge to your monthly premium — for as long as you have coverage. Here in St. Louis, where thousands of residents age into Medicare each year, understanding the deadlines is one of the most important things you can do before your 65th birthday.

Here's how the penalties work, who gets hit, and how to steer clear.

The Part B penalty: 10% for every year you wait

If you don't sign up for Part B when you're first eligible — and you don't have other qualifying coverage, like a job-based health plan from current employment — Medicare can charge a late-enrollment penalty.

The math is simple and stings: 10% added to your Part B premium for every full 12-month period you could have had Part B but didn't. That surcharge sticks around for the rest of your life on Medicare.

Your Initial Enrollment Period is a seven-month window: the three months before the month you turn 65, your birthday month, and the three months after. Miss it without qualifying coverage, and the clock starts.

The Part D penalty: small numbers, long tail

The Part D late-enrollment penalty is easier to overlook because the dollar amount looks small at first — but it also lasts a lifetime.

Medicare calculates it by multiplying 1% of the "national base beneficiary premium" by the number of full months you went without Part D or other creditable drug coverage after becoming eligible. That amount is rounded and added to your Part D premium every month, for as long as you're enrolled.

The trap: many people think they don't need drug coverage because they take few or no medications. But signing up later, after a diagnosis, means paying the penalty on top of whatever the plan costs.

What "creditable coverage" means — and why it matters

You can delay Part B or Part D without penalty if you have other coverage Medicare considers "creditable." That usually means:

• A health plan through your (or your spouse's) current employer
• For drug coverage, a plan that pays, on average, at least as much as standard Medicare Part D

Two important notes:

• COBRA and retiree coverage generally do not count as current employer coverage for Part B purposes. Many people learn this the hard way.
• Your drug plan (from an employer, union, or VA, for example) should send you a notice of creditable coverage each year. Keep it. You may need to prove you had it.

The 2027 landscape for Part D

Even if you never touch the penalty, Part D is changing in ways every St. Louis reader should know about for 2027:

• The out-of-pocket cap for covered drugs is $2,100 in 2026 and $2,400 in 2027. Once you hit that amount, you pay nothing more for covered prescriptions the rest of the year.
• The maximum deductible is $615 in 2026 and $700 in 2027.
• The old coverage gap ("donut hole") is gone as of 2025. Part D now has three phases instead of four.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the year in monthly installments instead of paying big bills at the pharmacy counter. It's optional and free to join.

Higher earners should also know that IRMAA surcharges — extra amounts added to Part B and Part D premiums — begin above $109,000 in income for a single filer in 2026.

Availability in the St. Louis area

St. Louis is in St. Louis city, where Medicare plan availability is set at the county level by the Centers for Medicare & Medicaid Services (CMS). That means the specific set of Part D and Medicare Advantage plans a St. Louis resident can choose from is the same across the city, but may differ from what a neighbor in St. Louis County or St. Charles County sees.

To compare what's actually offered where you live, use the Plan Finder at medicare.gov and enter your ZIP code. It's the only tool that shows the current, official list for your address.

Key dates to circle

• Initial Enrollment Period: The seven months around your 65th birthday.
• General Enrollment Period: January 1 – March 31, for people who missed their initial window (coverage starts the month after you enroll).
• Annual Enrollment Period: October 15 – December 7, when anyone with Medicare can change Part D or Medicare Advantage coverage for the following year.
• Medicare Advantage Open Enrollment: January 1 – March 31, a one-time chance each year to switch or drop a Medicare Advantage plan.