Medicare 2026

Medicare Part B and Part D penalties: know the deadlines

KANSAS CITY, Kan. — For most people turning 65, the difference between a clean Medicare start and a lifelong monthly penalty comes down to a handful of dates on the calendar. Miss the window to sign up for Part B or Part D, and the extra charge can follow you for as long as you have the coverage.

This guide walks through the enrollment windows that trigger — or prevent — late penalties, and how those dates line up with one another. If you live in Kansas City, your plan choices are set at the county level (Kansas City, Kan., sits in Wyandotte County), but the penalty rules are federal and apply the same way everywhere.

The window that starts everything: your Initial Enrollment Period

Your Initial Enrollment Period (IEP) is seven months long. It begins three months before the month you turn 65, includes your birthday month, and ends three months after. This is the cleanest way to sign up for Part A, Part B, and Part D without a penalty.

If you sign up in the three months before your birthday month, coverage generally starts the month you turn 65. If you sign up during or after your birthday month, coverage starts the month after you enroll. That timing matters if you're trying to line up Medicare with the end of another plan.

What happens if you miss it: the General Enrollment Period

If you don't sign up for Part B during your IEP and you don't qualify for a Special Enrollment Period, you'll have to wait for the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins the month after you enroll.

This is also when the Part B late penalty typically kicks in. The penalty is 10% of the standard Part B premium for each full 12-month period you were eligible for Part B but didn't take it. In most cases, you pay that extra amount every month for as long as you have Part B.

The Part D clock runs separately

Part D has its own timing rules, and they run alongside — not inside — the Part B rules. To avoid a Part D late enrollment penalty, you generally need to either sign up for a Part D plan when you're first eligible or maintain "creditable" drug coverage (coverage that's at least as good as standard Medicare drug coverage) without a gap of 63 days or more.

If you go 63 days or longer without creditable drug coverage after your IEP ends, Medicare adds a permanent surcharge to your Part D premium when you eventually sign up. The penalty is 1% of the national base beneficiary premium for every full month you went without, rounded to the nearest 10 cents, and it's added on for as long as you're enrolled in Part D.

Keep in mind that Part D also has an annual out-of-pocket cap and a maximum deductible — but those figures apply to what you pay for drugs, not to the penalty itself. The out-of-pocket cap is $2,100 in 2026 and $2,400 in 2027; the maximum deductible is $615 in 2026 and $700 in 2027.

When you can legitimately delay: Special Enrollment Periods

Not everyone should sign up at 65. If you or your spouse are still working and you have health coverage through that job, you can often delay Part B without a penalty. When that job coverage ends, you get an 8-month Special Enrollment Period (SEP) to sign up for Part B.

A few things trip people up here:

• COBRA and retiree coverage do not count as active employer coverage for the Part B SEP. The clock started when the active job coverage ended.
• The Part D SEP after losing creditable drug coverage is shorter — generally 63 days.
• Marketplace (ACA) coverage does not protect you from either penalty.

If you're not sure whether your current plan counts as creditable, ask the plan in writing. They're required to tell you each year.

How the dates line up during the year

Once you're in Medicare, two more windows show up on the calendar, and they matter for penalty planning too:

• Annual Enrollment Period, Oct. 15 – Dec. 7: You can join, switch, or drop a Part D or Medicare Advantage plan. Changes take effect Jan. 1.
• Medicare Advantage Open Enrollment, Jan. 1 – March 31: If you're already in a Medicare Advantage plan, you can switch to another one or go back to Original Medicare once during this window.

Neither of these windows lets you sign up for Part B for the first time — that's what the IEP, SEP, and General Enrollment Period are for. Mixing them up is one of the most common reasons people end up with a penalty they didn't see coming.

What to do if you think you already owe a penalty

If Medicare assesses a late enrollment penalty and you believe you had creditable coverage the whole time, you have the right to ask for a reconsideration. Keep any letters from former employers or insurers showing your coverage dates — those documents are what will settle the question.

Where to get personalized help

Penalty rules are federal, but your situation is personal. For answers tied to your own dates and coverage history:

• Visit medicare.gov for official enrollment period rules.
• Call 1-800-MEDICARE (1-800-633-4227), available 24/7.
• Contact your State Health Insurance Assistance Program (SHIP). In Kansas, SHIP counseling is free and unbiased.
• If you're delaying because of job coverage, ask your benefits administrator for written confirmation that your plan is creditable.