Medicare

Part D Penalty Calculator

Estimate how a Part D late-enrollment penalty is generally calculated after someone goes without creditable drug coverage.

Part D penalty estimate

Estimate the monthly Part D late-enrollment penalty.

Medicare generally multiplies 1% of the national base beneficiary premium by the number of full uncovered months someone went without Medicare drug coverage or other creditable prescription drug coverage.

Full uncovered months without Part D or creditable drug coverage2026 national base beneficiary premiumOptional monthly Part D plan premiumDid you have creditable drug coverage or Extra Help?

Uncovered months14

Medicare counts full months without Part D or creditable drug coverage.

Penalty percentage14%

1% for each full uncovered month.

Estimated monthly penalty$5.50

Rounded to the nearest ten cents.

Plan premium plus penalty$5.50

Your optional plan premium plus the estimated penalty.

Unrounded monthly estimate: $5.46. Estimated annual penalty: $66.00. Medicare says the national base beneficiary premium can change each year, so this penalty can change too.

What this estimate is for

The Part D late-enrollment penalty is generally based on the number of full uncovered months someone was eligible for Medicare drug coverage but did not have Part D or other creditable prescription drug coverage.

What you need before calculating

You need the number of full uncovered months and the current national base beneficiary premium. The base premium changes each year, so the penalty can change too.

Why it matters

A Part D penalty is added to the monthly drug plan premium and may last as long as someone has Medicare drug coverage, even if they switch plans later.

Use the estimate wisely

Medicare timing, penalties, and income rules can change the real answer.

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