Medicare Parts A, B, C, and D Explained in Plain English

If you are approaching 65 or helping a parent navigate Medicare for the first time, the alphabet soup of "Parts" can feel overwhelming. Here is a plain-English breakdown of Medicare Parts A, B, C, and D — what each covers, what it costs, and what decisions you need to make.

Medicare Part A: Hospital Insurance

Part A covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health services. Most people do not pay a monthly premium for Part A if they (or a spouse) worked and paid Medicare taxes for at least 10 years.

• Inpatient hospital stays (after a deductible per benefit period)
• Skilled nursing facility care (after a hospital stay of 3+ days)
• Hospice care
• Some home health services

Medicare Part B: Medical Insurance

Part B covers outpatient care — doctor visits, preventive services, lab work, durable medical equipment, and more. In 2024, the standard Part B premium is $174.70/month (higher for higher-income beneficiaries). Part B has an annual deductible, after which you generally pay 20% of Medicare-approved costs.

Medicare Part C: Medicare Advantage

Medicare Advantage plans are offered by private insurance carriers (like Humana, Aetna, and UnitedHealthcare) and bundle Part A and Part B coverage — often with added benefits like dental, vision, hearing, and prescription drug coverage. Many plans have $0 monthly premiums. You still pay your Part B premium.

• Bundled Part A + Part B coverage from a private carrier
• Usually includes Part D drug coverage
• Often includes dental, vision, and hearing benefits
• Many plans have $0 additional monthly premium
• Network restrictions apply — you typically must use in-network providers

Medicare Part D: Prescription Drug Coverage

Part D provides prescription drug coverage. If you have Original Medicare (Parts A and B) and not a Medicare Advantage plan that includes drug coverage, you should add a standalone Part D plan. Failing to enroll in Part D when first eligible can result in a late enrollment penalty.

Medicare Supplement (Medigap): Filling the Gaps

Medigap plans are not an official Medicare "Part" but they are important. These supplemental policies from private carriers help cover the cost-sharing gaps in Original Medicare — deductibles, copays, and the 20% coinsurance that Medicare leaves you responsible for.

Which Path Is Right for You?

The choice between Medicare Advantage and Original Medicare + Medigap + Part D depends on your health needs, your doctors and hospitals, your prescription medications, and your budget. There is no universally correct answer — it is a highly individual decision.

Quest Insurance helps seniors nationwide compare Medicare options side by side and choose based on their specific situation. Our Medicare guidance is free — there is no cost to you.