Medicare is federal health insurance for people 65 and older and some younger people with disabilities or certain medical conditions. When you enroll in Part A and Part B, you have Original Medicare. You can keep it and add separate drug or supplemental insurance, or join a Medicare Advantage plan, also called Part C.

What Are the Parts of Medicare?

Each part covers a different type of care or offers a different way to receive your benefits:

  • Part A, Hospital Insurance: Helps cover inpatient hospital care, skilled nursing facility care under certain conditions, hospice, and some home health care.
  • Part B, Medical Insurance: Helps cover doctors' services, outpatient care, preventive services, medical equipment such as walkers and wheelchairs, and other medically necessary care.
  • Part C, Medicare Advantage: A private-plan alternative to Original Medicare. These plans provide Part A and Part B benefits and usually include Part D.
  • Part D, Drug Coverage: Helps pay for prescription drugs. You can receive it through a separate drug plan with Original Medicare or through most Medicare Advantage plans.

The official Parts of Medicare guide explains what each part covers.

Original Medicare or Medicare Advantage?

Once you have Part A and Part B, you can choose between two main ways to get your coverage:

Original Medicare is run by the federal government. You can see any doctor or hospital in the United States that takes Medicare. You may add a separate Part D plan and may be able to buy Medicare Supplement Insurance, also called Medigap, to help with certain out-of-pocket costs.

Medicare Advantage plans are offered by Medicare-approved private insurance companies. They must cover nearly all medically necessary services Original Medicare covers and may offer additional benefits. Plans often have a network of doctors and hospitals you can use for covered care. You may need a referral to see a specialist. For some services, the plan may need to approve coverage before you receive care. This is called prior authorization. Each plan has its own costs and rules.

Neither option is automatically best for everyone. Your doctors, prescriptions, travel, budget, and comfort with plan rules all matter.

You cannot use Medigap to pay your share of costs in Medicare Advantage. Part C is an alternative way to receive your Medicare benefits, rather than additional insurance you need on top of Original Medicare.

Is Medicare Free?

Usually not. Most people do not pay a monthly fee, called a premium, for Part A because they or a spouse paid Medicare taxes long enough. Part B has a monthly premium, including when you join Medicare Advantage. You may also pay premiums for drug coverage, Medigap, or a Medicare Advantage plan.

When you receive care, you may have other costs. A deductible is an amount you pay before coverage starts paying for certain services. After that, your share may be a percentage of the covered cost, called coinsurance, or a fixed amount, called a copayment.

Original Medicare itself has no annual limit on Part A and Part B out-of-pocket spending. Supplemental insurance may pay some of those costs; how much it pays depends on the policy. Medicare Advantage plans do have an annual limit for covered Part A and Part B services, although the amount varies by plan.

Does Medicare Cover Everything?

No. Original Medicare generally does not cover long-term care that mainly helps with daily tasks such as bathing and dressing, most routine dental care, routine eye exams for glasses, hearing aids, or care outside the United States. Some Medicare Advantage plans offer certain additional benefits, but details and limits vary.

Before scheduling non-emergency care, check whether the service is covered. With Original Medicare, ask whether the doctor takes Medicare. With Medicare Advantage, check the plan’s network and any approval requirements.

How Do You Get Started?

Some people are enrolled automatically, while others must sign up through Social Security. Your timing may depend on whether you already receive Social Security or Railroad Retirement Board benefits and whether you have qualifying job-based insurance.

Once Part A and Part B are in place, review:

  • Your preferred doctors and hospitals
  • Your prescriptions and pharmacies
  • Care you expect to need
  • Monthly premiums and possible out-of-pocket costs
  • Whether you travel or live in more than one location
  • When you can buy Medigap and whether an insurer can turn you down

Start with your enrollment dates. Once you know when Parts A and B begin, compare how your doctors and prescriptions would be covered under Original Medicare and Medicare Advantage.

Medicare policy sources last checked: October 8, 2026.