Parts A, B, C, D, plus Medigap. What each piece does, what it costs, and the deadlines that actually matter.
The short answer
Medicare is federal health insurance primarily for people 65 and older. Part A covers hospital care, Part B covers doctor visits and outpatient care, Part D covers prescriptions, and Part C (Medicare Advantage) is a private all-in-one alternative that bundles them. Medigap is a private supplement that pays Original Medicare's deductibles and coinsurance. The central choice is Original Medicare plus Medigap and Part D versus Medicare Advantage, and the enrollment deadlines around age 65 carry lifelong penalties if missed.
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Medicare, made simple
A, B, C, D, and Medigap, plus the deadlines that bite.
Read the transcript
Medicare, made simple — the alphabet, decoded in one minute.
Part A covers hospitals. Part B, doctors. Part D, prescriptions. Part C bundles it all privately as Medicare Advantage — and Medigap fills Original Medicare's gaps.
The big decision: Original Medicare with Medigap costs more monthly but works with nearly any doctor. Advantage plans cost little upfront — with networks and approvals attached.
And the deadlines bite. You get a seven-month window around your sixty-fifth birthday — enrolling late in Part B can mean a penalty that lasts for life.
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Medicare comes in parts. Here's the stack.
Part A: the hospital layer
Inpatient care, skilled nursing after a hospital stay, hospice. Premium-free for most people who paid payroll taxes for 10+ years, the layer you've already bought.
Part B: the medical layer
Doctor visits, outpatient care, preventive services. This one has a standard monthly premium, adjusted upward for higher incomes (a surcharge called IRMAA).
Part D: the drug layer
Prescription coverage through private plans. Good news that's still sinking in: annual out-of-pocket drug costs are now capped by law.
Part C: the bundle
Medicare Advantage: a private, all-in-one alternative to A + B that usually includes D plus extras like dental and vision. Often low or $0 premium, with networks and prior authorizations attached.
Medigap: the gap-filler
Not a part but a private supplement that pays Original Medicare's deductibles and coinsurance. Pairs with a separate Part D plan. Higher premium, near-total cost predictability.
The big fork at 65.
Original Medicare + Medigap + Part D
- ●Any doctor in the country who accepts Medicare, no networks
- ●Predictable costs: Medigap absorbs most of the cost-sharing
- ●Higher monthly premiums
- ●No prior-authorization gatekeeping for most care
Medicare Advantage (Part C)
- ●Often low or $0 extra premium, frequently with dental and vision
- ●Networks: your doctors and hospitals must be in-plan
- ●Prior authorization is common for bigger services
- ●Out-of-pocket costs rise with usage, up to a yearly cap
More premium and more freedom, or less premium and more rules. Your health, travel habits, and budget decide, not the loudest TV ad.
The deadlines that actually matter.
Medicare is forgiving about almost nothing on the calendar. These are the dates to circle.
64¾
Your enrollment window opens
The initial enrollment period runs 7 months: the 3 months before your 65th-birthday month, that month, and the 3 after.
65
The Part B decision
Enroll, or document qualifying employer coverage. Enrolling late without it means a premium penalty that lasts for life, on Part B and Part D both.
65+
Medigap's golden six months
For 6 months after your Part B start, Medigap is guaranteed-issue regardless of health. Miss it, and in most states insurers can decline or surcharge you later.
Every fall
October 15 – December 7
Annual open enrollment: switch Medicare Advantage or drug plans. Worth a yearly check even if you're happy: plans change their networks and formularies.
Three expensive assumptions.
Tap a card to flip it.
One honest note before you decide.
No private agency offers every plan available in your area, including us. The official, complete picture always lives at medicare.gov and 1-800-MEDICARE, and any advisor worth your time will point you there without being asked.
One more thing worth knowing early: if you're still working at 65 with qualifying employer coverage, you can usually delay Part B without penalty, but 'qualifying' has rules, so confirm before you skip the deadline rather than after.
Turning 65 soon, or helping a parent who is?
We'll walk the fork together: what each path costs, what each path restricts, and which deadlines apply to your exact birthday.
Questions people ask
- What are the parts of Medicare?
- Part A covers hospital and inpatient care and is premium-free for most people who paid payroll taxes for 10 or more years. Part B covers doctor visits, outpatient care, and preventive services for a monthly premium that rises with income. Part D covers prescriptions through private plans, with annual out-of-pocket drug costs now capped by law. Part C, called Medicare Advantage, is a private all-in-one alternative to A and B that usually includes D, while Medigap is a separate private supplement that pays Original Medicare's cost-sharing.
- When do I have to sign up for Medicare?
- Your initial enrollment period runs 7 months: the 3 months before your 65th-birthday month, that month, and the 3 months after. Enrolling in Part B or Part D late without qualifying employer coverage means a premium penalty that lasts for life. Medigap is guaranteed-issue for 6 months after your Part B start, and each fall from October 15 to December 7 you can switch Medicare Advantage or drug plans.
- Is Medicare free?
- Part A usually is, for anyone with 10 or more years of payroll taxes. Part B has a monthly premium that is adjusted upward for higher incomes, drug coverage costs extra, and cost-sharing is real. Medicare is a budget line in retirement, so it helps to plan for it like one.
- What is the difference between Medicare Advantage and Medigap?
- Medicare Advantage plans often have low or $0 extra premiums and extras like dental and vision, but they come with networks, prior authorizations, and out-of-pocket costs that rise with usage up to a yearly cap. Medigap pairs with Original Medicare and a separate Part D plan, costs more monthly, and delivers predictable costs plus access to any doctor in the country who accepts Medicare. Neither is universally better; your health, travel habits, and budget decide. The complete picture of plans in your area always lives at medicare.gov and 1-800-MEDICARE.
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