Medicare 101
A plain-language foundation for understanding Medicare before selecting private coverage.
The four parts have different jobs
Part A covers qualifying inpatient hospital care, skilled nursing facility care, hospice, and some home health services. Part B covers medically necessary outpatient care and many preventive services. Together, A and B form Original Medicare. Part C is Medicare Advantage, a private-plan way to receive A and B benefits. Part D covers qualifying outpatient prescriptions through approved private plans. The letters describe functions, not four policies everyone must purchase.
Official source: Medicare: Parts of Medicare ↗
Two ways to receive medical coverage
With Original Medicare, the federal program pays its share when you use eligible providers; you can separately consider Part D and Medigap. With Medicare Advantage, the private plan administers Part A and Part B and usually includes Part D. An Advantage plan may set network and authorization rules, while Original Medicare has no annual Part A/B out-of-pocket maximum without other coverage.
Official source: Medicare: Original versus Advantage ↗
Costs before plan shopping
In 2026 most people pay no Part A premium; the standard Part B premium is $202.90 per month and the Part B deductible is $283 for the year. Original Medicare Part A has a $1,736 inpatient deductible per benefit period. A particular Advantage or Part D premium, copay, formulary, and maximum require that plan’s current documents. Do not treat a zero plan premium as zero total cost.
Official source: Medicare: 2026 costs ↗
Enrollment is a separate decision
For most people first eligible at 65, the Initial Enrollment Period spans seven months around the birthday month. Some receive Parts A and B automatically; others must sign up through Social Security. The month you apply can affect the effective date. Confirm those dates before changing employer insurance or joining a private plan, which has its own enrollment rules.
Official source: Medicare: When to sign up ↗ · Medicare: How to sign up ↗ · SSA: Sign up for Medicare ↗
What to verify before selecting a plan
Write down both effective dates, your current coverage, employers and payer order, doctors, hospitals, exact prescriptions and pharmacy. Compare the annual premium plus plausible care costs, and check the plan service area. If you are still working, do not assume COBRA or retiree coverage creates the same Part B enrollment protection as coverage based on current employment.
Official source: Medicare: Who pays first ↗ · Medicare: Joining a plan ↗ · Medicare: COBRA coverage ↗