Medicare choices, laid out clearly.

Medicare is the federal health insurance program for people 65 and older and for some younger people with disabilities or certain conditions. The decisions you make when you first enroll can affect your costs and choices for years, so it pays to understand the structure before comparing plans.

The parts of Medicare

• Part A (hospital insurance) covers inpatient hospital stays, skilled nursing facility care, hospice and some home health care. Most people do not pay a premium for Part A.
• Part B (medical insurance) covers doctor visits, outpatient care, preventive services and medical equipment, with a monthly premium.
• Part C, Medicare Advantage, is an alternative way to get Part A and Part B benefits through a private plan approved by Medicare. Many plans include drug coverage and extras, but most use provider networks and prior authorization.
• Part D is prescription drug coverage offered by private plans, either on its own alongside Original Medicare or built into a Medicare Advantage plan.

People with Original Medicare often add a Medicare Supplement (Medigap) policy to help with deductibles and coinsurance. You generally cannot use Medigap with a Medicare Advantage plan.

Enrollment windows

Your Initial Enrollment Period is seven months: the three months before the month you turn 65, that month, and the three months after. Signing up late for Part B or Part D without other qualifying coverage can mean a lifelong late-enrollment penalty. Each year, the Open Enrollment Period from October 15 to December 7 lets you switch between Original Medicare and Medicare Advantage or change drug plans, and the Medicare Advantage Open Enrollment Period from January 1 to March 31 allows one change for people already in an Advantage plan.

Comparing plans

Use the official Medicare Plan Finder at Medicare.gov to check that your drugs, pharmacies and doctors are covered, and compare total yearly cost, not just the premium. The guides below explain the trade-offs in more detail.