Health · Chapter 17 · Medicare Basics
Medicare Enrollment Periods & Penalties
Definition
Initial: 7 months — 3 before, the birth month, 3 after. General: Jan 1–Mar 31 (coverage the next month) with a 10% lifetime Part B penalty per 12-month delay. Special: workers covered by a 20+ employee group plan may delay penalty-free and enroll within 8 months of retiring. Annual Open Enrollment (switch Original↔Advantage): Oct 15–Dec 7; MA Open Enrollment (MA enrollees only): Jan 1–Mar 31 — one switch to another MA plan or back to Original + Part D.
Exam tip
Delay is penalty-free ONLY behind a COBRA-size (20+) employer group where the group pays primary. Under 20 employees → Medicare is primary; enroll at 65.
Easy to confuse with
These are what this term gets tested against — if you can't tell them apart cold, drill the contrast.
Related terms