Medicare Part B & Part D
Medicare Part B and Part D Penalty Calculator – 2026
Estimate possible Medicare Part B and Part D late enrollment penalties using one simple uncovered-months field.
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Enter Penalty Details
Shared for Part B and Part D. Default is 0.
Used to estimate the Part B penalty.
Used to estimate the Part D penalty.
Estimated Results
Monthly Estimate
Enter the number of months and click Calculate.
How the Penalty Works
- Part B: 10% per year for each full 12-month period you delayed enrolling when eligible.
- Part D: 1% per month for every month you went without creditable prescription drug coverage.
Ways to Avoid a Penalty
- Enroll when first eligible.
- Keep proof of employer group health coverage.
- Maintain creditable prescription drug coverage.
- Use a Special Enrollment Period when available.
Medicare Part B enrollment forms
CMS 40B
to Enroll in Part B — Sent in by the Medicare Beneficiary.
Download CMS 40B
CMS L-564
to show proof of Employer Coverage — Sent in by Employer.
Download CMS L-564
This calculator is for educational estimates only. Actual penalties are determined by Medicare/CMS and may vary based on eligibility, employer coverage, creditable coverage, and Special Enrollment Period rules.