Medicare is the federal government's health insurance program available to anyone age 65 and older. It’s also available to people younger than 65 who have certain disabilities or end-stage renal disease.

To get coverage, you can sign up for Original Medicare (Part A and Part B) or a Medicare Advantage Plan (Part C).

Additional coverage is available through Part D and Medigap.

What is Medicare Part A?

This is the hospital insurance part of Medicare, which generally covers short-term inpatient care at hospitals and skilled nursing centers, as well as some home care and hospice services. There may a deductible or co-pay for some care, services and equipment.

Medicare Part A coverage is free to people 65 and older who worked in the United States for at least 10 years and paid Medicare taxes (an automatic deduction for most workplaces). If you don’t meet these conditions, you can buy Medicare Part A coverage for a monthly premium.

What is Medicare Part B?

This is the medical insurance part of Medicare, which generally covers preventive services, doctor visits, outpatient care, and care and equipment needed to treat a disease or condition.

There is a monthly premium to get Medicare Part B coverage. Many people choose to have this premium automatically deducted from their Social Security checks.

What is Medicare Part C?

Also called Medicare Advantage Plans, these are Medicare-approved health plans provided by private companies.

You can enroll in a Medicare Advantage Plan instead of enrolling in Medicare Part A and Part B.

Medicare Advantage Plans cover all Part A and Part B benefits; many also offer coverage for prescription drugs, as well as vision and dental benefits.

Each plan sets its own premiums, deductibles, co-pays, provider networks, and rules for coverage.

Medicare Advantage Plans have limits on annual out-of-pocket costs, which Original Medicare does not.

What is Medicare Part D?

This is the prescription drug coverage part of Medicare. Offered by private insurance companies, there are many different plans to choose from that provide varying levels of coverage for prescription drugs.

Medicare Part D is supplemental insurance that has a monthly premium, as well as deductibles and co-pays, which are set by the plan providers.

You can sign up for a Part D plan if you have Original Medicare (Part A and Part B), but not if you are enrolled in a Medicare Advantage Plan (Part C) because those plans typically already include prescription drug coverage.

What is Medigap?

This is supplemental insurance coverage that helps pay for costs Original Medicare doesn’t cover, like co-pays and deductibles.

Medigap policies are offered by private insurance companies, which set the monthly premiums for each plan.

Medigap policies are only available to people enrolled in Original Medicare (Part A and Part B).