What Is Medicare? A Complete Guide to Parts A, B, C, and D
Medicare isn't free, and it doesn't cover everything. Here's what each part actually covers, what it costs in 2026, and how to avoid the most common enrollment mistakes.
Medicare is the federal health insurance program for Americans 65 and older (and some younger people with disabilities). Most people assume it's free and covers everything once you turn 65 — neither is true. Understanding the parts, the costs, and the enrollment deadlines now can save you thousands of dollars and a lifetime late-enrollment penalty later.
The Four Parts of Medicare
- Part A (Hospital Insurance): Covers inpatient hospital stays, skilled nursing facilities, and hospice. Premium-free for most people who paid Medicare taxes for 10+ years.
- Part B (Medical Insurance): Covers doctor visits, outpatient care, preventive services, and medical equipment. Has a monthly premium.
- Part C (Medicare Advantage): Private insurance plans that bundle Parts A and B (often with drug coverage) into one plan, usually with extra benefits like dental or vision.
- Part D (Prescription Drug Coverage): Covers prescription medications. Optional, but skipping it can trigger a permanent penalty if you enroll later.
What Medicare Actually Costs in 2026
- Part A: $0/month for most people (premium-free); up to $518/month if you didn't work the required 40 quarters
- Part B: $185/month standard premium (higher for incomes above $106,000 single / $212,000 married — this is called IRMAA)
- Part B deductible: $257/year, then you typically pay 20% coinsurance with no out-of-pocket maximum
- Part D: Varies by plan, typically $30–$80/month, plus a deductible up to $590
💡 Original Medicare (Parts A and B) has no annual out-of-pocket maximum — a serious illness could cost tens of thousands of dollars in coinsurance. Most people cover this gap with either a Medicare Supplement (Medigap) policy or a Medicare Advantage plan, which caps annual out-of-pocket costs.
Medicare Advantage vs. Original Medicare + Medigap
Original Medicare plus a Medigap supplement plus a Part D drug plan gives you the most provider flexibility (any doctor who accepts Medicare, nationwide) but usually costs more per month. Medicare Advantage (Part C) typically has lower or $0 premiums and includes an out-of-pocket cap, but restricts you to a network and requires referrals for specialists in many plans. Neither is universally better — it depends on how much you travel, which doctors you want to keep, and how much monthly premium you can absorb.
Enrollment Deadlines You Cannot Miss
- Initial Enrollment Period: 7-month window around your 65th birthday (3 months before, the month of, 3 months after)
- General Enrollment: January 1 – March 31 if you missed your initial window (coverage starts the following July)
- Special Enrollment: If you have employer coverage from an active job (yours or a spouse's) at 65, you can delay Medicare penalty-free until that coverage ends
💡 Missing your enrollment window without qualifying employer coverage triggers permanent penalties: Part B costs 10% more for every 12-month period you delayed, for as long as you have Medicare. Part D has a similar lifetime penalty. Mark your calendar the moment you turn 64.5.
What Medicare Doesn't Cover
Original Medicare does not cover routine dental, vision, or hearing aids, long-term custodial care (like an extended nursing home stay for daily living help), or care received outside the United States. Many Medicare Advantage plans add limited dental and vision benefits, which is one of their biggest selling points.
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