Medicare Part B is part of original Medicare, which is an insurance plan that the United States federal government offers.

Part B covers medical care and supplies for diagnosing, treating, and preventing medical conditions, including injuries and illnesses. It also accounts for some preventive care, such as flu vaccinations.

Several out-of-pocket costs apply to services that Medicare funds under Part B, including an annual premium, a deductible, and coinsurance payments.

In this article, we break down the coverage, costs, and eligibility criteria for Medicare Part B.

Glossary of Medicare terms

We may use a few terms in this article that can be helpful to understand when selecting the best insurance plan:

  • Deductible: This is an annual amount a person must spend out of pocket within a certain period before an insurer starts to fund their treatments.
  • Coinsurance: This is the percentage of treatment costs that a person must self-fund. For Medicare Part B, this is 20%.
  • Copayment: This is a fixed dollar amount a person with insurance pays when receiving certain treatments. For Medicare, this usually applies to prescription drugs.
  • Out-of-pocket costs: An out-of-pocket cost is the amount a person must pay for medical care when Medicare does not pay the total cost or offer coverage. These costs can include deductibles, coinsurance, copayments, and premiums.
Was this helpful?
a senior woman having a mammograms  which is covered by medicare part b Share on Pinterest
Medicare Part B can help cover the cost of health screenings.

Medicare Part B covers a range of services to treat and prevent medical conditions. These services include:

  • Doctor’s visits: Part B covers routine checkups and telemedicine, as well as specialist visits.
  • Health screenings: These include bone density scans, colorectal cancer screenings, and mammograms.
  • Medical equipment: Part B covers durable medical equipment, including hospital beds, wheelchairs, and walkers.
  • Ambulance transport: Coverage includes emergency ground transport when other types of transport would be unsafe.
  • Clinical studies: The insurance pays for certain aspects that the hospital conducting the clinical research will not cover, such as doctor’s visits.
  • Limited medication: Medicare Part B covers certain medications, such as those relating to the use of durable medical equipment, including nebulized medications.
  • Rehabilitation therapies: Eligible rehabilitation therapies include speech, occupational, and physical therapy when they are necessary for improving physical function and enabling independent living.

Read more detailed information about coverage under Medicare Part B.

Premiums, deductibles, and coinsurances apply to Medicare Part B.

For example, Medicare Part B beneficiaries pay a monthly premium. A person must also meet a deductible before Medicare Part B covers the costs of healthcare services.

Premiums and deductibles usually increase every year. In 2021, the Part B monthly premium is $148.50 for a person who receives $88,000 a year or less in income.

Individuals with higher annual incomes pay more substantial monthly premiums.

People who are financially unable to support the cost of a Part B premium may apply and qualify for other federal assistance programs, such as Medicaid, to offset out-of-pocket costs.

In addition to a monthly premium, Medicare Part B recipients must also pay a deductible for services before Medicare will fund any costs. In 2021, the Medicare Part B deductible is $203.

After meeting the yearly deductible, beneficiaries pay 20% of the Medicare-approved amount for most healthcare services that they receive under Part B. There is no out-of-pocket limit for Part B, and out-of-pocket costs apply throughout the membership year.

Find out more about the costs of Medicare Part B.


Retirees from some organizations may qualify for Medicare Part B reimbursement.

Many retired federal employees continue their healthcare coverage through the Federal Employees Health Benefits (FEHB) Program. Some may also choose to enroll in Medicare Part B when they reach 65 years of age.

In some cases, the FEHB Program may reimburse federal retirees for the cost of their Medicare Part B premium.

The enrollment process for Medicare Part B differs depending on a person’s situation.

Most people enroll during the Initial Enrollment Period, which is a 7-month window that includes the month of their 65th birthday and the 3 months either side. During this time, they also become eligible for Medicare Part A.

However, people who are under 65 years of age but have end stage renal disease, amyotrophic lateral sclerosis (ALS), or other disabilities will receive automatic enrollment in Part B after 2 years of receiving disability benefits.

Some people choose to skip enrollment in Medicare Part B due to the cost of the monthly premium or because they have additional private insurance.

Individuals who do not sign up during the Initial Enrollment Period have another opportunity to enroll during the Open Enrollment Period, which runs from October 15 to December 7 each year.

However, people enrolling after the initial period will pay a late penalty for the duration of their coverage unless they meet certain requirements.

To meet eligibility requirements for Medicare Part B, an individual must be a U.S. citizen or have been a legal resident for a minimum of 5 consecutive years. They must also be 65 years of age or older.

People under 65 years of age may qualify if they have received disability benefits for at least 2 years from the Railroad Retirement Board or Social Security Administration.

Individuals with amyotrophic lateral sclerosis or end stage renal disease also qualify for Medicare Part B as soon as they are eligible for disability benefits.

Find out more about eligibility for Medicare Part B.

An individual only needs to complete a Medicare Part B application if they refused Medicare Part B during their Initial Enrollment Period but wish to enroll during general enrollment, or if they are still in the Initial Enrollment Period but did not enroll in Part B and Part A at the same time

The application process involves completing form CMS 40B, which applicants can find on the Centers for Medicare & Medicaid Services website.

Medicare Part A and Part B are both parts of original Medicare, but they cover different aspects of medical care.

Medicare Part B covers outpatient services. Medicare Part A, however, funds in-hospital care or inpatient services, such as hospital admission costs, hospice services, and skilled nursing care.

Costs also differ between Medicare Part A and Part B. Most people receive Part A for free, but beneficiaries pay a premium for Part B that varies according to their income.

We compared Parts A and B in more detail.

Medicare Part C is an alternative to original Medicare that private insurers administer. However, the federal government contracts them. Medicare Part C, or Medicare Advantage, bundles benefits from Parts A, B, and D.

People with an Advantage plan do not also need Part B, as they will already have the benefits under their bundled coverage.

Read more about the differences between Medicare Parts B and C.

Both Medicare Part B and Part D cover medications. However, Medicare Part D only covers prescription medication. Part B, on the other hand, provides very limited drug coverage.

For instance, Part B covers end stage renal disease drugs and injections for osteoporosis but excludes most prescription drugs that a person buys at their pharmacy and takes at home.

Recipients buy Medicare Part D plans through private insurance companies to cover pharmacy purchases. Usually, Part D plans include an annual premium and a copayment for each prescription drug.

Learn more about the differences between Medicare Parts B and D.

Medicare Part B covers supplies and services that help a doctor diagnose and treat medical conditions.

It also covers some preventive care. Medicare Part B costs include a deductible, a premium, and coinsurances.

Most people become eligible at 65 years of age, but some exceptions apply.