We publish unbiased product reviews; our opinions are our own and are not influenced by payment we receive from our advertising partners. Learn more about how we review products and read our advertiser disclosure for how we make money.

There are four parts of Medicare: Part A, Part B, Part C, and Part D. In general, the four Medicare parts cover different services, so it's essential that you understand the options so you can pick your Medicare coverage carefully.

Key Takeaways

  • Medicare is the national health insurance program available to people age 65 or older, younger people with disabilities, and people with end-stage renal disease.
  • There are four parts to Medicare: A, B, C, and D.
  • Part A is automatic and includes payments for treatment in a medical facility.
  • Part B is automatic if you do not have other healthcare coverage, such as through an employer or spouse.
  • Part C, called Medicare Advantage, is a private-sector alternative to traditional Medicare.
  • Part D covers prescription drug benefits.

Maybe you’re getting close to the age of 65 or simply want to understand how Medicare works so you can help a family member or friend. While some people who sign up for Medicare are retired, others are still working. Whatever your situation, you become eligible for Medicare when you reach 65 and, in most cases, must enroll. In fact, if you are already receiving Social Security, you'll be enrolled in Medicare automatically the month you turn 65. The card will arrive in the mail.

Currently, more than 60 million people are enrolled in Medicare.

“Anyone who has been approved and has received Social Security disability income benefits for two years qualifies for Medicare Parts A and B,” says Chris Cooper, CFP®, ChFC, EA, MSFS, president, Chris Cooper & Company, San Diego, Calif.

Medicare has evolved over the years and now has four parts. While some are mandatory, others are optional.

Medicare Part A: Hospital Insurance

Medicare Part A covers the costs of hospitalization. When you enroll in Medicare, you receive Part A automatically. For most people, there is no monthly cost, but there is a $1,408 deductible in 2020.

Services covered under part A may include surgeries, inpatient care in hospitals, skilled nursing facilities, hospice care, home healthcare services, and inpatient care in a religious non-medical healthcare institution.

This sounds straightforward, but it's not. For example, Part A covers in-home hospice care but does not cover a stay in a hospice facility.

Additionally, if you’re hospitalized, a deductible applies, and if you stay for more than 60 days, you have to pay a portion of each day’s expenses. If you’re admitted to the hospital multiple times during the year, you may need to pay a deductible each time.

Medicare Part B: Doctors and Tests

Medicare Part B covers a long list of medical services including doctor’s visits, medical equipment, outpatient care, outpatient procedures, purchase of blood, mammograms, cardiac rehabilitation, and cancer treatment.

You’re not required to enroll in Part B if you don’t have “creditable coverage” from another source, such as an employer or spouse's employer.

You pay a monthly premium for Part B. In 2020, the cost was $144.60, up from $135.50 in 2019. If you're on Social Security, this may be deducted from your monthly payment.

If you don’t enroll and you don’t have creditable coverage from another source, you may have to pay a penalty if you enroll later.

The annual deductible for Part B is $198 in 2020. Once you meet the deductible, you pay 20% of the Medicare-approved cost of the service, provided your healthcare provider accepts Medicare assignment. But beware: There is no cap on your 20% out-of-pocket expense.

For example, if your medical bills for a certain year were $100,000, you could be responsible for up to $20,000 of those charges, plus the charges incurred under Part A and D umbrellas. There is no lifetime maximum.

Kathryn B. Hauer, MBA, CFP®, EA, a financial advisor with Wilson David Investment Advisors in Aiken, S.C., and author of Financial Advice for Blue Collar America, explains:

“Chilling, and potentially devastating for chronic illnesses like cancer—the American Medical Association estimates that Medicare users without Medigap can spend 25% to 64% of their income on medical expenses."

On the other hand, you pay nothing for most preventive services, such as diabetes screenings and flu shots, if you receive those services from a provider who accepts Medicare assignment.

What Parts A and B Don't Cover

The largest and most important item that traditional Medicare doesn’t cover is long-term care if the only care you need is custodial. If you are diagnosed with a chronic condition that requires ongoing long-term personal care assistance, the kind that requires an assisted-living facility, Medicare will cover none of the cost. However, Medicare will cover the costs for acute-care hospital services, for patients who are transferred from an intensive care or critical care unit. Services covered could include head trauma treatment or respiratory therapy. 

70%

The percentage of people over the age of 65 who will need longer-term care at some point.

According to Carlos Dias Jr., wealth manager, Excel Tax & Wealth Group, Lake Mary, Fla.,

“Medicare was never meant to pay for long-term care. To take care of these expenses, look into long-term care insurance, a life insurance policy with a long-term care rider (add-on), a specifically designed long-term care annuity (versus an annuity with a chronic care rider) or even a life settlement, which will convert an old life insurance policy into a set amount of funds.”

Other expenses that are not covered include routine dental or eye care, dentures, and hearing aids.

Medicare Part C: Medicare Advantage

Also known as Medicare Advantage, Part C is an alternative to traditional Medicare coverage. Coverage normally includes all of Parts A and B, a prescription drug plan (Part D), and, depending on your choice of a Medicare Advantage plan, other possible benefits.

Part C is administered by Medicare-approved private insurance companies that collect your Medicare payment from the federal government.

Depending on the plan, you may or may not need to pay an additional premium for Part C. You still need to pay your Medicare Part B premium. You don’t have to enroll in a Medicare Advantage plan but for many people, these plans can be a better deal than paying separately for Parts A, B, and D. Beneficiaries will still pay separate premiums if they don’t choose to have the Part “C/D” premium taken out of their Social Security check.

If you've been pleased by the coverage of a Health Maintenance Organization (HMO), you might find similar services using Medicare Advantage.

Medicare Part D: Prescription Drugs

Prescription drug coverage, known as Part D, is also administered by private insurance companies. Part D is required unless you have a prescription drug plan from another source, including any Medicare Advantage plan. Depending on your plan, you may have to meet a yearly deductible before your plan begins covering your eligible drug costs.

Medicare prescription drug plans have a coverage gap—a temporary limit on what the drug plan will cover. The coverage gap is often called the “doughnut hole,” and this gap kicks in after you and your plan have spent a certain amount in combined costs. For example, in 2020 the donut hole occurs once you and your insurer combined have spent $4,020 on prescriptions.

Once you have paid $6,350 in out-of-pocket costs for covered drugs, you have reached the level of "catastrophic coverage," for 2020 in out-of-pocket costs for covered drugs. This means you are out of the prescription drug “donut hole” and your prescription drug coverage begins paying for most of your drug expenses again.

Many states have insurance options that will close the coverage gap, but these may require paying an additional premium.

Medicare Advantage vs. Medigap

People who only have Medicare Parts A, B, and D may incur sizable bills not covered by Medicare. To close these gaps, recipients can enroll in some form of Medigap insurance or in a Medicare Advantage plan (see Part C, above).

One important thing to know about Medigap: It only supplements Medicare and is not a stand-alone policy. If your doctor doesn't take Medicare, Medigap insurance will not pay for the procedure.

Insurance agents are not allowed to sell Medigap to participants of Part C, Medicare Advantage.

Medigap coverage is standardized by Medicare but offered by private insurance companies. According to, Patrick Traverse, founder of MoneyCoach, Mt. Pleasant, S.C.,

“I recommend that my clients purchase Medigap policies to cover their needs. Even though the premiums are higher, it is much easier to plan for them than what could be a large out-of-pocket outlay they might have to face if they had lesser coverage."