How do the different parts of Medicare work together?

Orientation
Last updated: 
April 10, 2026
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The short answer

Medicare is divided into parts that cover different things. Part A covers hospital stays, Part B covers doctors and outpatient care, Part C is Medicare Advantage (a private plan alternative), and Part D covers prescription drugs.

The full explanation

Original Medicare is made up of two parts. Part A covers inpatient hospital stays, skilled nursing facility care after a qualifying hospital stay, hospice, and some home health services. Most people don't pay a monthly premium for Part A because it's based on your work history. Part B covers outpatient care, meaning doctor visits, lab tests, preventive services, and medical equipment. Part B does have a monthly premium.Together, Parts A and B form the foundation. But they don't cover everything, and they come with cost-sharing, which means deductibles and coinsurance you pay out of pocket. Many people add coverage to fill those gaps.Part C, known as Medicare Advantage, is an alternative way to get your Medicare benefits. Instead of using Parts A and B directly through the federal government, you enroll in a private insurance plan that is approved by Medicare. These plans often include drug coverage and sometimes offer extras like dental or vision. The tradeoff is that they typically have networks of preferred providers.Part D is standalone prescription drug coverage. You can add it to Original Medicare, and it's often built into Medicare Advantage plans.Some people also buy a Medigap policy, which is supplemental insurance that helps cover the cost-sharing gaps in Original Medicare. Medigap works alongside Parts A and B but cannot be used with Medicare Advantage.The parts don't all have to be used together in the same way. Your combination depends on your health needs, your finances, and which doctors and medications matter most to you.

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