It depends on your employer's size and your coverage. Get this wrong and you can owe a permanent penalty — here is how to get it right.
A checklist can organize questions, but your work and insurance circumstances determine the appropriate steps. Ask the employer benefits administrator how the plan pays when Medicare eligibility begins, and use the official Medicare sign-up instructions.
Do not treat them as the same. Medicare’s sign-up guidance distinguishes situations that can affect special enrollment eligibility. Verify the type of coverage you actually have before postponing enrollment.
Ask who pays first, whether the coverage is based on current employment, whether the drug coverage is creditable and what documents are available when employment ends. Save the answers and notices for your enrollment file.
Confirm the effective date of replacement coverage and the coordination rules before canceling. This site does not evaluate your employer plan or determine eligibility. If the instructions are unclear, contact Medicare or Social Security directly with your circumstances.
| Item | What it means |
|---|---|
| Active-employment coverage | Check coordination and special enrollment rules. |
| Retiree coverage or COBRA | Check the separate official sign-up guidance. |
| Drug coverage notice | Keep evidence of creditable coverage. |
Official sources: Medicare.gov official reference · Medicare.gov official reference
Last reviewed: 2026-10-12 — the added explanation and linked sources only. Existing calculator outputs and earlier content require separate validation. Educational information; not individualized insurance, tax or medical advice.
You can usually delay Part B without penalty and stay on your employer's group plan. When that coverage ends, you get an 8-month Special Enrollment Period to sign up for Part B penalty-free. Many people still take premium-free Part A at 65.
Medicare usually becomes your primary coverage, so you generally should enroll at 65 during your Initial Enrollment Period — delaying can leave gaps and trigger penalties. Confirm with your benefits administrator.
If you delay without qualifying employer coverage, the Part B late penalty is 10% per full year — permanently. Always verify whether your coverage counts as creditable before delaying.
One catch: you cannot contribute to an HSA once you're enrolled in any part of Medicare, including premium-free Part A. If you want to keep contributing, you may need to delay all of Medicare — plan the timing carefully.
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New here? Start free →Often yes, if your employer has 20+ employees and you have creditable group coverage. You get an 8-month Special Enrollment Period to enroll in Part B penalty-free when that coverage ends.
Not if you have qualifying employer coverage from an employer with 20+ employees. Without creditable coverage, the Part B penalty is 10% per year, permanently.
No. You cannot contribute to an HSA once enrolled in any part of Medicare, including premium-free Part A.
Figures on this page are verified against U.S. government primary sources: