Medicare

Part B Penalty Calculator

Estimate how a Part B late-enrollment penalty is generally calculated when someone delayed Part B without qualifying coverage.

Part B penalty estimate

Estimate the monthly Part B late-enrollment penalty.

Medicare generally adds 10% of the standard Part B premium for each full 12-month period you could have had Part B but did not sign up, unless a Special Enrollment Period or another exception applies.

Full months delayed without Part BStandard monthly Part B premiumDo you qualify for a Special Enrollment Period or similar exception?

Full 12-month penalty periods2

24 delayed months ÷ 12, rounded down to full years.

Penalty percentage20%

10% for each full 12-month period.

Estimated monthly penalty$40.58

Added to the standard Part B premium.

Estimated monthly Part B premium$243.48

Standard premium plus the estimated penalty.

Estimated annual penalty: $486.96. Medicare may calculate and round final amounts differently, and this does not determine whether you qualify for a Special Enrollment Period, Medicare Savings Program, or another exception.

What this estimate is for

The Part B late-enrollment penalty is generally based on how many full 12-month periods someone delayed Part B after they were eligible.

What you need before calculating

You need the number of full 12-month periods without Part B and the current standard Part B premium. Employer coverage and Special Enrollment Period rules can change the answer.

Why it matters

Part B timing mistakes can create long-term premium penalties or coverage gaps, especially when someone retires, loses employer coverage, or leaves COBRA.

Use the estimate wisely

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

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