Medicare Basics: Parts A, B, C, and D

The four parts

Medicare has four parts. Part A covers hospital stays and is usually premium-free if you paid Medicare taxes long enough. Part B covers outpatient and physician care for a monthly premium (about $185 in 2025). Together, Parts A and B are "Original Medicare."

Part C, or Medicare Advantage, is a private all-in-one alternative that bundles A, B, and usually D, often adding dental, vision, and hearing. Part D is standalone prescription drug coverage that pairs with Original Medicare.

The big decision

The central choice at 65 is between two paths: Original Medicare plus a Medigap supplement plus a Part D drug plan, or a Medicare Advantage plan. Original Medicare + Medigap offers predictable costs and nationwide provider access with no network; Advantage often has lower premiums and bundled extras but uses networks and prior authorization.

Neither is universally better. The right path depends on your doctors, whether you travel, your medications, and how you weigh predictable costs against a lower monthly premium.

Frequently asked questions

Is Medicare free?

Part A is usually premium-free, but Part B has a monthly premium, and drug and supplemental coverage cost extra. Medicare is not entirely free.

Do I need Part D?

If you take prescriptions and choose Original Medicare, yes — and enrolling on time avoids a lifelong late-enrollment penalty. Many Advantage plans include drug coverage.