What is a Medicare Special Enrolment Period?

The best-known one follows employment: when coverage from a large employer where you or your spouse actively works comes to an end, you have eight months to take Part B without a penalty, and two months to join a drug or Advantage plan. Moving out of your plan's area, losing Medicaid or Extra Help, and a plan leaving your county all open their own windows.

Each window has its own length and its own paperwork, and they do not stack. The two that catch people out are COBRA — which does not extend the Part B window — and retiree coverage, which is not treated as active employment.

An estimate for planning, not a quote. Medicare and the Marketplace set your real figures.