Medicare is the federal health insurance program for people who are 65 or older, or those under 65 who may qualify because of a disability or another special situation. Medicare helps millions of American seniors and disabled individuals cover some of their health care costs.

Medicare also offers important choices in how you receive benefits – whether through Original Medicare or through a Medicare-approved private insurer that offers prescription drug coverage and additional benefits like vision, hearing, dental, and more. The different parts of Medicare help cover the costs of specific services.

Medicare is available to United States citizens and legal residents who have lived in the United States for at least 5 years in a row. Medicare is individual insurance. It doesn't cover spouses or dependents.

You may become eligible to receive Medicare benefits based on any one of the following:

You are age 65 or older.

You are younger than 65 with a qualifying disability and have received Social Security disability benefits for 24 months.

You are any age with a diagnosis of End-Stage Renal Disease (ESRD) or Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig’s Disease).

Most people sign up for both Part A (Hospital Insurance) and Part B (Medical Insurance) when they’re first eligible (usually when they turn 65). Generally, there are risks to signing up later, like a gap in your coverage or having to pay a penalty. However, in some cases, it might make sense to sign up later.

Your first chance to sign up (Initial Enrollment Period)

Generally, when you turn 65. This is called your Initial Enrollment Period. It lasts for 7 months, starting 3 months before you turn 65, and ending 3 months after the month you turn 65.

Avoid the penalty: If you miss your 7-month Initial Enrollment Period, you may have to wait to sign up and pay a monthly late enrollment penalty for as long as you have Part B coverage. The penalty goes up the longer you wait. You may also have to pay a penalty if you have to pay a Part A premium, also called “Premium-Part A.”

When your coverage starts

The date your coverage starts depends on which month you sign up during your Initial Enrollment Period. Coverage always starts on the first of the month.

If you qualify for Premium-free Part A: Your Part A coverage starts the month you turn 65. (If your birthday is on the first of the month, coverage starts the month before you turn 65.)

Part B (and Premium-Part A): Coverage starts based on the month you sign up.

If you sign up: Coverage starts:

Before the month you turn 65 The month you turn 65

The month you turn 65 The next month

1 month after you turn 65 2 months after you sign up

2 or 3 months after you turn 65 3 months after you sign up

Signing up for Premium-free Part A later

You can sign up for Part A any time after you turn 65. Your Part A coverage starts 6 months back from when you sign up or when you apply for benefits from Social Security (or the Railroad Retirement Board). Coverage can’t start earlier than the month you turned 65. After your Initial Enrollment Period ends, you can only sign up for Part B and Premium-Part A during one of the other enrollment periods.

Between January 1-March 31 each year (General Enrollment Period)

You can sign up between January 1-March 31 each year. This is called the General Enrollment Period. Your coverage starts July 1. You might pay a monthly late enrollment penalty, if you don’t qualify for a Special Enrollment Period.

Special Situations (Special Enrollment Period)

There are certain situations when you can sign up for Part B (and Premium-Part A) during a Special Enrollment Period without paying a late enrollment penalty. A Special Enrollment Period is only available for a limited time. If you don’t sign up during your Special Enrollment Period, you’ll have to wait for the next General Enrollment Period and you might have to pay a monthly late enrollment penalty.

When coverage starts

Generally, coverage starts the month after you sign up.

Special situations include:

You have health insurance through a job and still working

You can sign up for Part A and Part B any time as long as:

• You have group health plan coverage.

• You or your spouse (or a family member if you’re disabled) is working for the employer that provides your health coverage.

You also have 8 months to sign up after you or your spouse (or your family member if you’re disabled) stop working or you lose group health plan coverage (whichever happens first).

Your 8-month Special Enrollment Period starts when you stop working, even if you choose COBRA or other coverage that’s not Medicare.

You’re a volunteer, serving in a foreign country

Certain situations for people with TRICARE

Situations that don’t qualify for a Special Enrollment Period:

• Your COBRA coverage or retiree coverage ends. If you miss your 8-month window when you stopped working, you’ll have to wait until the next General Enrollment Period to sign up.

• You have or lose your Marketplace coverage.

• You have End-Stage Renal Disease (ESRD).

The different parts of Medicare help cover specific services:

Medicare Part A (Hospital Insurance)

Part A covers inpatient hospital stays, care in a skilled nursing facility, hospice care, and some home health care.

Medicare Part B (Medical Insurance)

Part B covers certain doctors' services, outpatient care, medical supplies, and preventive services.

Medicare Part C (Medicare Advantage)

Medicare Advantage is a Medicare-approved plan from a private company that offers an alternative to Original Medicare for your health and drug coverage. These “bundled” plans include Part A, Part B, and usually Part D.

Medicare Part D (Drug Coverage)

Helps cover the cost of prescription drugs (including many recommended shots or vaccines).

Medicare Supplement (Medigap)

Extra insurance you can buy from a private company that helps pay your share of costs in Original Medicare. Policies are standardized, and in most states named by letters, like Plan G or Plan K. The benefits in each lettered plan are the same, no matter which insurance company sells it.

With Medicare, you have options in how you get your coverage. Once you enroll, you’ll need to decide how you’ll get your Medicare coverage. There are 2 main ways:

Original Medicare (Part A & B)

Original Medicare includes Medicare Part A (Hospital Insurance) and Medicare Part B (Medical Insurance). You pay for services as you get them. When you get services, you’ll pay a deductible at the start of each year, and you usually pay 20% of the cost of the Medicare-approved service, called coinsurance. If you want drug coverage, you can add a separate drug plan (Part D).

Original Medicare pays for much, but not all, of the cost for covered health care services and supplies. A Medicare Supplement Insurance (Medigap) policy can help pay some of the remaining health care costs, like copayments, coinsurance, and deductibles. Some Medigap policies also cover services that Original Medicare doesn't cover, like emergency medical care when you travel outside the U.S.

Medicare Advantage (Part C)

Medicare Advantage is Medicare-approved plan from a private company that offers an alternative to Original Medicare for your health and drug coverage. These “bundled” plans include Part A, Part B, and usually Part D. Plans may offer some extra benefits that Original Medicare doesn’t cover — like vision, hearing, and dental services. Medicare Advantage Plans have yearly contracts with Medicare and must follow Medicare’s coverage rules. The plan must notify you about any changes before the start of the next enrollment year.

Each Medicare Advantage Plan can charge different out-of-pocket costs and they can also have different rules for how you get services.

Medicare prescription drug coverage (Part D)

Medicare drug coverage helps pay for prescription drugs you need. To get Medicare drug coverage, you must join a Medicare-approved plan that offers drug coverage (this includes Medicare drug plans and Medicare Advantage Plans with drug coverage).

Each plan can vary in cost and specific drugs covered, but must give at least a standard level of coverage set by Medicare. Medicare drug coverage includes generic and brand-name drugs. Plans can vary the list of prescription drugs they cover (called a formulary) and how they place drugs into different "tiers" on their formularies.

Plans have different monthly premiums. You’ll also have other costs throughout the year in a Medicare drug plan. How much you pay for each drug depends on which plan you choose.

Original Medicare covers most, but not all of the costs for approved health care services and supplies. After you meet your deductible, you pay your share of costs for services and supplies as you get them. There’s no limit on what you’ll pay out-of-pocket in a year unless you have other coverage (like Medigap, Medicaid, or employee or union coverage).

Services covered by Medicare must be medically necessary. Medicare also covers many preventive services, like shots and screenings. If you go to a doctor or other health care provider that accepts the

Medicare-approved amount, your share of costs may be less. If you get a service that Medicare doesn’t cover, you pay the full cost.

With Original Medicare, you can:

• Go to any doctor or hospital that takes Medicare, anywhere in the U.S. Find providers that work with Medicare.

• Join a separate Medicare drug plan (Part D) to get drug coverage.

• Buy a Medicare Supplement Insurance (Medigap) policy to help lower your share of costs for services you get.

If you're not lawfully present in the U.S., Medicare won't pay for your Part A and Part B claims, and you can't enroll in a Medicare Advantage Plan or a Medicare drug plan.

Medicare Advantage bundles your Part A, Part B, and usually Part D coverage into one plan. Plans may offer some extra benefits that Original Medicare doesn’t cover — like vision, hearing, and dental services.

You join a plan offered by Medicare-approved private companies that follow rules set by Medicare. Each plan can have different rules for how you get services, like needing referrals to see a specialist. Costs for monthly premiums and services you get vary depending on which plan you join.

Plans must cover all emergency and urgent care, and almost all medically necessary services Original Medicare covers. Some plans tailor their benefit packages to offer additional benefits to treat specific conditions.

With Medicare Advantage, you:

• Need to use doctors who are in the plan’s network (for non-emergency or non-urgent care).

• May pay a premium for the plan in addition to the monthly Part B premium. Plans may have a $0 premium or may help pay all or part of your Part B premiums.

• Can’t buy or use separate supplemental coverage (like Medigap).

You must have both Part A and Part B to join a Medicare Advantage Plan.

Medicare Supplement Insurance (Medigap) is extra insurance you can buy from a private company that helps pay your share of costs in Original Medicare.

• You need both Part A and Part B to buy a Medigap policy.

• Some Medigap policies offer coverage when you travel outside the U.S.

• Generally, Medigap policies don’t cover long-term care (like care in a nursing home), vision, dental, hearing aids, private-duty nursing, or prescription drugs.

• If you’re under 65, you might not be able to buy a Medigap policy, or you may have to pay more.

Medigap policies are standardized, and in most states named by letters, like Plan G or Plan K. The benefits in each lettered plan are the same, no matter which insurance company sells it.

Price is the only difference between policies with the same letter sold by different companies.

Get the lowest price: If you don’t buy a Medigap policy within 6 months of when you first get both Part A and Part B, you may not be able to buy a policy or you may pay more.

Note: If you're in a Medicare Advantage Plan or other Medicare plan, your plan may have different rules. But, your plan must give you at least the same coverage as Original Medicare. Some services may only be covered in certain facilities or for patients with certain conditions.

In general, Part A covers:

• Inpatient care in a hospital

• Skilled nursing facility care

• Nursing home care (inpatient care in a skilled nursing facility that’s not custodial or long-term care)

• Hospice care

• Home health care

2 ways to find out if Medicare covers what you need

1. Talk to your doctor or other health care provider about why you need certain services or supplies. Ask if Medicare will cover them. You may need something that's usually covered but your provider thinks that Medicare won't cover it in your situation. If so, you'll have to read and sign a notice. The notice says that you may have to pay for the item, service, or supply.

2. Find out if Medicare covers your item, service, or supply by visiting Medicare.gov

Medicare coverage is based on 3 main factors

1. Federal and state laws.

2. National coverage decisions made by Medicare about whether something is covered.

3. Local coverage decisions made by companies in each state that process claims for Medicare. These companies decide whether something is medically necessary and should be covered in their area.

Note: If you're in a Medicare Advantage Plan or other Medicare plan, your plan may have different rules. But, your plan must give you at least the same coverage as Original Medicare. Some services may only be covered in certain facilities or for patients with certain conditions.

Part B covers 2 types of services

• Medically necessary services: Services or supplies that are needed to diagnose or treat your medical condition and that meet accepted standards of medical practice.

• Preventive services: Health care to prevent illness (like the flu) or detect it at an early stage, when treatment is most likely to work best. You pay nothing for most preventive services if you get the services from a health care provider who accepts assignment.

Part B covers things like:

• Clinical research

• Ambulance services

• Durable medical equipment (DME)

• Mental health

  • Inpatient

  • Outpatient

  • Partial hospitalization

• Limited outpatient prescription drugs

2 ways to find out if Medicare covers what you need

1. Talk to your doctor or other health care provider about why you need certain services or supplies. Ask if Medicare will cover them. You may need something that's usually covered but your provider thinks that Medicare won't cover it in your situation. If so, you'll have to read and sign a notice. The notice says that you may have to pay for the item, service, or supply.

2. Find out if Medicare covers your item, service, or supply by visiting Medicare.gov

Medicare coverage is based on 3 main factors

1. Federal and state laws.

2. National coverage decisions made by Medicare about whether something is covered.

3. Local coverage decisions made by companies in each state that process claims for Medicare. These companies decide whether something is medically necessary and should be covered in their area.

Medicare doesn't cover everything.

Some of the items and services Medicare doesn't cover include:

• Long-Term Care (also called custodial care)

• Most dental care

• Eye exams related to prescribing glasses

• Dentures

• Cosmetic surgery

• Acupuncture

• Hearing aids and exams for fitting them

• Routine foot care

If you need services Medicare doesn't cover, you'll have to pay for them yourself unless you have other insurance or a Medicare health plan that covers them.

If you're not lawfully present in the U.S., Medicare won't pay for your Part A and Part B claims, and you can't enroll in a Medicare Advantage Plan or a Medicare drug plan.

Part A & Part B Premiums

Most people don’t pay a monthly premium for Part A.

You usually don't pay a monthly premium for Part A if you or your spouse paid Medicare taxes while working for a certain amount of time. This is sometimes called "premium-free Part A."

If you don't qualify for premium-free Part A, you can buy Part A.

If you aren't eligible for premium-free Part A, you may be able to buy Part A. You'll pay up to $499 each month in 2022. If you paid Medicare taxes for less than 30 quarters, the standard Part A premium is $499. If you paid Medicare taxes for 30–39 quarters, the standard Part A premium is $274.

Everyone pays a monthly premium for Part B.

Most people will pay the standard Part B premium amount. The standard Part B premium amount in 2022 is $170.10. If your modified adjusted gross income as reported on your IRS tax return from 2 years ago is above a certain amount, you'll pay the standard premium amount and an Income Related Monthly Adjustment Amount (IRMAA). IRMAA is an extra charge added to your premium.

If you (or your spouse) are still working, Medicare works a little differently. Here are some things to know if you’re still working when you turn 65.

Do I still need to sign up for Medicare when I turn 65?

It depends on how you get your health insurance now and the number of employees that are in the company where you (or your spouse) work.

Generally, if you have job-based health insurance through your (or your spouse’s) current job, you don’t have to sign up for Medicare while you (or your spouse) are still working. You can wait to sign up until you (or your spouse) stop working or you lose your health insurance (whichever comes first).

• If you’re self-employed or have health insurance that’s not available to everyone at the company: Ask your insurance provider if your coverage is employer group health plan coverage (as defined by the IRS.) If it’s not, sign up for Medicare when you turn 65 to avoid a monthly Part B late enrollment penalty.

• If the employer has less than 20 employees: You might need to sign up for Medicare when you turn 65 so you don’t have gaps in your job-based health insurance. Check with the employer.

• If you have
  COBRA coverage: Sign up for Medicare when you turn 65 to avoid gaps in coverage and a monthly Part B late enrollment penalty. If you have COBRA before signing up for Medicare, your COBRA will probably end once you sign up.

Keep in mind that:

• Most people qualify to get Part A without paying a monthly premium. If you qualify, you can sign up for Part A coverage starting 3 months before you turn 65 and any time after you turn 65 — Part A coverage starts up to 6 months back from when you sign up or apply to get benefits from Social Security (or the Railroad Retirement Board).

• If you have a Health Savings Account, you and your employer should stop contributing to it 6 months before you sign up for Part A (or apply to start getting Social Security benefits) to avoid a tax penalty.

Do I need to get Medicare drug coverage (Part D)?

You can get Medicare drug coverage once you sign up for either Part A or Part B. You can join a Medicare drug plan or Medicare Advantage Plan with drug coverage anytime while you have job-based health insurance, and up to 2 months after you lose that insurance.

Even if you have a Special Enrollment Period to join a plan after you first get Medicare, you might have to pay the Part D late enrollment penalty. To avoid the Part D late enrollment penalty, don’t go 63 days or more in a row without Medicare drug coverage or other creditable drug coverage.

If you have other drug coverage: Ask your drug plan if it’s “creditable drug coverage.”

Each year, your plan must tell you if your non-Medicare drug coverage is creditable coverage. Keep this information — you may need it when you’re ready to join a Medicare drug plan.

Medicare is federal health insurance for anyone age 65 and older, and some people under 65 with certain disabilities or conditions.

Medicaid is a joint federal and state program that provides health coverage for some people with limited income and resources. Medicaid offers benefits, like nursing home care, personal care services, and assistance paying for Medicare premiums and other costs.

If you qualify, you can have both Medicare and Medicaid.