Medicare late-enrollment penalties: separate the rules

By My Coverage Relay · Updated September 24, 2026

A Medicare late-enrollment penalty is usually an ongoing premium charge, not a one-time fee. The useful way to avoid confusion is to keep three separate questions: did you need Part A, did you need Part B, and did you maintain creditable prescription coverage?

Part A and Part B

The Part A penalty concerns people who must buy Part A because they do not qualify for premium-free coverage. The premium can rise by 10%, generally for twice the number of years enrollment was delayed.

Part B generally adds 10% for each full 12-month period you could have enrolled but did not, unless a relevant exception applies. It generally continues while you have Part B. A qualifying Special Enrollment Period or Medicare Savings Program may change the result.

Part D uses a different clock

After your initial drug-enrollment opportunity, going 63 consecutive days or more without Part D or other creditable drug coverage can trigger a penalty when you later join. The calculation generally uses 1% of the national base beneficiary premium for each full uncovered month, rather than a percentage of your chosen plan’s premium. That base changes by year.

You do not avoid this issue simply by taking no prescriptions. The rule concerns coverage, not whether you happened to need medication during that period. Extra Help can protect against a Part D penalty while you receive it.

One kind of protection does not prove another

A COBRA drug benefit may be creditable for Part D while COBRA does not extend the employment-related Part B enrollment window. A short drug gap may avoid a drug penalty without giving you permission to join any plan on any date. Check the enrollment opportunity as well as the penalty rule.

Keep a coverage record

• Annual creditable prescription coverage notices.
• Employment and employer group coverage dates.
• Applications, confirmations and effective dates.
• Termination notices and proof of any qualifying special event.
• Copies of correspondence about a penalty or reconsideration.

If you receive a notice

Read which part the charge concerns, the period counted and the deadline to dispute it. Gather evidence for any months that should not be counted. Follow the specific reconsideration instructions instead of assuming switching insurers removes the charge. Avoid stopping premiums while a question is under review without understanding the consequences.

Common question: Can an agent promise my penalty will be removed? No. An agent can help you organize the history and understand the notice; the responsible program makes the decision.

Avoid confusing a penalty rule with an enrollment right

The 63-day drug-coverage threshold is not a general shopping window. A person may need to submit a plan application sooner to use the appropriate enrollment opportunity and prevent a gap. Likewise, proving prior drug coverage does not establish that a delay in Part B was protected. Keep the medical and drug coverage timelines separate.

How to reconstruct an incomplete history

1. List every month from your first Medicare eligibility to the present.
2. Mark medical and drug coverage in separate columns.
3. Identify the employer or insurer that can verify each period.
4. Request replacement notices or coverage records for missing months.
5. Compare the documented history with the period in the penalty notice.

Do not guess on an application merely to fill an empty date field. A benefits administrator, prior insurer or the responsible program may be able to confirm it. Keep a note of where each date came from.

Prevent the next problem

Store annual creditable-coverage notices even in years when you make no change. Before ending a policy, ask how you will prove its coverage dates later. If someone says a delay is safe, ask which Medicare rule supports that answer and keep the written explanation.

Is a higher premium always a penalty? No. Income-related adjustments, a plan’s own premium change and late-enrollment penalties are different charges. Read the notice’s reason before deciding which review or appeal process to use.