Medicare Part D Late Enrollment Penalty: Calculation and Appeals

A Part D late-enrollment penalty may apply if, after your initial enrollment opportunity, you go 63 days or more without Part D or other creditable coverage. It is a monthly amount added to your plan premium, generally for as long as you have Part D, rather than a one-time charge.

How the 2026 estimate works

Multiply 1% of the national base beneficiary premium by the number of full uncovered months that count toward the penalty. The 2026 national base premium is $38.99. Round the result to the nearest ten cents. This base amount is not necessarily your own plan’s premium.

These examples illustrate the formula; your plan determines the months that count. The national base premium changes by year, so the dollar penalty can change even when the number of months stays the same. Switching plans does not normally erase it.

When the penalty does not apply

People with qualifying creditable coverage or Extra Help generally do not pay a Part D late penalty. Creditable coverage is expected to pay at least as much, on average, as Medicare drug coverage. Keep the plan’s annual notice and records showing when coverage began and ended. Taking no prescriptions does not by itself exempt you.

Part B has a different enrollment and penalty system. Do not use a Part D notice as proof that you may delay Part B. A pharmacy discount program is not a substitute for insurance.

If you disagree with the notice

1. Read the plan’s explanation and check the uncovered months.
2. Gather creditable-coverage notices, coverage dates and other requested evidence.
3. Request reconsideration using the form and address in the notice, normally within 60 days of its date.
4. Keep paying the billed premium, including the penalty, while the request is reviewed.
5. Keep the decision and check that any correction or refund is reflected by the plan.

An independent Medicare contractor reviews the reconsideration. If you submit late, explain the reason. A calculator cannot decide eligibility, count every special circumstance or replace that review.

Related coverage questions

• Medicare Part D: Coverage Choices, Enrollment and Costs
• Medicare Part D Costs: Premiums, Deductibles and Annual Limits
• How to Compare Medicare Part D Plans

Official sources

• Avoid late enrollment penalties
• Creditable prescription drug coverage
• Drug coverage basics
• How much does Medicare drug coverage cost?