Key takeaways:
Medicare Part B is an optional part of original Medicare that covers outpatient services and some medications not covered by Medicare Part A or Part D.
You may have to pay a monthly penalty if you don’t sign up for Part B when you’re first eligible.
Your monthly premium for Medicare Part B depends on your income.
If you're turning 65 and considering enrolling in Medicare, you may be eligible to enroll in both Part A and Part B. These two parts, known as original Medicare, collectively provide basic healthcare coverage.
Medicare Part A covers hospital services, while Part B covers medical services received in an outpatient setting. However, Part B requires a monthly premium, and there are rules about when you can enroll.
What is Medicare Part B?
Medicare Part B is an optional program that’s part of original Medicare and helps cover the cost of outpatient services. These services include regular checkups with your healthcare professional, lab tests, and certain medications.
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You automatically qualify for Medicare Part B if you’re eligible for premium-free Part A. However, if you have to pay a premium for Part A, there are certain requirements you must meet to be eligible for Part B.
What does Medicare Part B cover?
Medicare Part B covers a range of medically necessary and preventive services.
Medically necessary services and supplies
Medically necessary services and supplies are those that are used to diagnose and treat a medical condition. Some examples of medically necessary services commonly covered by Part B are:
Visits with a healthcare professional
Outpatient therapy
In addition to other medically necessary supplies, Part B covers certain types of durable medical equipment, such as:
Blood sugar meters
Continuous positive airway pressure (CPAP) machines
Preventative services
Preventive services are those that help prevent or diagnose illnesses at an early stage, when treatment is most beneficial. Some preventive services covered under Part B are:
Immunizations, including the COVID-19 vaccine
Is Medicare Part A free? Your eligibility for premium-free Medicare Part A depends on your work and tax-paying history.
Surprising Medicare-covered items: Beyond the long list of common services and supplies covered by Medicare, there are some, like acupuncture and nutrition therapy services, that may surprise you.
Medicare does not cover everything. From weight-loss medications to routine dental care, here are some healthcare expenses not covered by Medicare.
List of medications covered by Medicare Part B
Medicare Part B typically only covers medications that are given in a healthcare professional’s office or in another outpatient setting. This includes:
Medications used with medical equipment like infusion pumps or nebulizers
Antigens
Erythropoiesis-stimulating agents for people with end-stage renal disease or anemia related to other conditions
Medications for end-stage renal disease that are taken by mouth
Blood-clotting factors for people with hemophilia
Vaccines for flu, pneumococcal pneumonia, hepatitis B, and more
Transplant or immunosuppressive medications in certain cases
Cancer medications taken by mouth
Starting in 2023, individuals whose full Medicare coverage ended 36 months after a kidney transplant can choose to continue Part B coverage for immunosuppressive medications by paying a premium — as long as they don’t have other qualifying insurance.
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Typically, you can expect to pay 20% of the Medicare-approved amount for medications covered under Part B. This is after you’ve paid your Part B deductible.
What is not covered by Medicare Part B?
Medicare Part B does not cover:
Routine dental care
Routine vision care
Routine physical exams
You can use the Medicare website to check if a specific test or item is covered under Medicare Part B.
How much is Medicare Part B?
Your monthly premium amount for Medicare Part B depends on your income. The income thresholds and set premium amounts are subject to change every year.
Medicare Part B premiums for 2025
The 2025 standard premium for Medicare Part B is $185 per month. According to the Centers for Medicare & Medicaid Services, most people will pay this amount. To qualify for the standard premium in 2025, individual earners had to have reported a 2023 income of $106,000 or less — or $212,000 or less for joint filers.
In general, what you pay in Part B premiums depends on the modified adjusted gross income shown on your tax return. Those who earn more money pay more in premiums, according to a graduated scale. There are five payment levels above the standard monthly premium, with the max premium being $628.90 per month in 2025 for the wealthiest tax filers.
For some people, Part B monthly premiums are automatically deducted from Social Security or Railroad Retirement Board benefits. If you don’t get these benefits, you’ll get a bill for your premiums every 3 months that you can pay online, directly from your checking or savings account, or by mail.
To find out when you’ll likely be eligible for Medicare or to get an estimate of how much you can expect to pay in premiums, use the Medicare eligibility and premium tool.
Medicare Part B deductible and coinsurance
Unlike your Medicare Part B premiums, your Part B deductible isn’t based on your income. For 2025, the Medicare Part B deductible is $257 for all beneficiaries.
After you meet your Part B deductible, you will typically pay 20% of the Medicare-approved amount for:
Most outpatient visits
Outpatient therapy
Durable medical equipment such as blood sugar meters, oxygen equipment, and walkers
Medicare Part B enrollments
Failing to apply for Medicare Part B when you’re first eligible could cost you in late fees. Here’s a guide on how to enroll in Medicare Part B and make sure you don’t face any penalties.
Initial enrollment period
When you first become eligible for Medicare at age 65, you have a 7-month initial enrollment period to apply for Part B. This window to enroll begins 3 months before you turn 65 and lasts for 3 months after your birthday month. So, for example, if your 65th birthday is in June, your initial enrollment period begins in March (3 months before your birthday) and lasts until September (3 months after your birthday).
Late-enrollment penalty
If you sign up for Part B after your initial enrollment period, you’ll be charged a late-enrollment penalty of 10% for each 12-month period you could have had Part B. So the longer you go without Part B, the higher the penalty. However, you will not pay the penalty if you meet certain special enrollment period requirements.
Special enrollment period
If you miss your initial enrollment period, there are certain situations that may qualify you for a special enrollment period. This is a limited window outside of the general enrollment period during which you can enroll in Part B without facing a late-enrollment penalty. You can learn more about how to sign up for a special enrollment period on the Medicare website. Special enrollment periods are assessed individually on a case-by-case basis.
The following situations may qualify you for a special enrollment period for Medicare Part B and Part A:
Losing Medicaid coverage
Moving back to the U.S. after living abroad
Leaving a facility, such as a nursing home or rehabilitation hospital, where you were previously staying
Losing employer-sponsored or union health coverage, including COBRA coverage
Qualifying for Extra Help to assist with Medicare prescription medication coverage costs
Receiving incorrect or misleading information from a Medicare or plan representative that leads to your enrollment in a plan
General enrollment period
If you didn’t sign up for Medicare Part B during your initial enrollment period and you don’t qualify for a special enrollment period, you’ll have to wait for the next general enrollment period. And you may have to pay a monthly late-enrollment penalty once you sign up.
General enrollment runs from January 1 to March 31 annually. You can sign up for Medicare Part B during this period if one of these situations applies to you:
You didn’t enroll in Medicare Part B when you were first eligible.
You canceled Part B without having other insurance but would like to enroll again.
You didn’t enroll for Part B within 8 months of no longer working or your employer-sponsored or union health plan ending (whichever happened first).
If you apply for Medicare Part B between January 1 and March 31, your coverage will start the month after you sign up. You can enroll in Medicare online, by fax, or by mail.
Medicare Part B additional resources
In addition to www.medicare.gov, here are a few other sources for Medicare-related information:
Medicare Rights Center: The Medicare Rights Center is a nonprofit organization that helps people who are covered by Medicare understand their rights and how the system works. Call their free national hotline at 1-800-333-4114 or visit www.medicareinteractive.org for assistance.
Center for Medicare Advocacy: This nonprofit advocacy organization promotes health equity and access to quality healthcare for people who have Medicare. The Center for Medicare Advocacy offers free resources, like self-help checklists, to help you appeal a Medicare denial.
State Health Insurance Assistance Programs (SHIPs): SHIPs offer free, unbiased counseling and assistance programs at the state level. To find information about your state SHIP office, call 1-877-839-2675.
Frequently asked questions
Medicare Part A primarily covers inpatient hospital care and certain types of care after hospitalization. Most people don’t pay premiums for Part A if they or their spouse paid Medicare payroll taxes for at least 10 years.
Medicare Part B covers outpatient care such as physician visits, preventive services, and certain types of medical equipment. Part B has a monthly premium, which varies based on income.
Enrolling in Medicare Part B is optional, however, you might face penalties for not enrolling when you first become eligible. If you don't have insurance through an employer or other creditable source, you may want to enroll in Part B when you first become eligible to avoid these penalties.
Without Part B, you could face significant out-of-pocket expenses for necessary medical services. Additionally, if you delay signing up for Part B and don’t have other coverage, you could face a gap in coverage and a late-enrollment penalty in the future.
Medicare Part A primarily covers inpatient hospital care and certain types of care after hospitalization. Most people don’t pay premiums for Part A if they or their spouse paid Medicare payroll taxes for at least 10 years.
Medicare Part B covers outpatient care such as physician visits, preventive services, and certain types of medical equipment. Part B has a monthly premium, which varies based on income.
Enrolling in Medicare Part B is optional, however, you might face penalties for not enrolling when you first become eligible. If you don't have insurance through an employer or other creditable source, you may want to enroll in Part B when you first become eligible to avoid these penalties.
Without Part B, you could face significant out-of-pocket expenses for necessary medical services. Additionally, if you delay signing up for Part B and don’t have other coverage, you could face a gap in coverage and a late-enrollment penalty in the future.
The bottom line
Medicare Part B typically covers medications delivered in a healthcare professional’s office or outpatient setting. It also covers a range of medically necessary services and some preventive care services.
You may want to delay signing up for Medicare Part B if you currently have health insurance that offers you the coverage you need. But remember, you may have to pay a monthly penalty down the line if you don’t sign up for Part B when you’re first eligible.
Be mindful of the enrollment periods for Medicare Part B to ensure you don’t miss out on the opportunity to sign up and avoid late-enrollment penalties. Visit www.medicare.gov or call 1-800-633-4227 to learn more.
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References
Center for Medicare Advocacy. (n.d.). Self help materials.
Centers for Medicare & Medicaid Services. (2023). 2024 Medicare Parts A & B premiums and deductibles.
Centers for Medicare & Medicaid Services. (2024). 2025 Medicare Parts A & B premiums and deductibles.
Centers for Medicare & Medicaid Services. (2024). Original Medicare (Part A and B) eligibility and enrollment.
Medicare.gov. (n.d.). Avoid late enrollment penalties.
Medicare.gov. (n.d.). Compare original Medicare and Medicare Advantage.
Medicare.gov. (n.d.). Coronavirus disease 2019 (COVID-19) vaccine.
Medicare.gov. (n.d.). Durable medical equipment (DME) coverage.
Medicare.gov. (n.d.). Estimate my Medicare eligibility and premium.
Medicare.gov. (n.d.). How to drop Part A and Part B.
Medicare.gov. (n.d.). Incontinence supplies and adult diapers.
Medicare.gov. (n.d.). Prescription drugs (outpatient).
Medicare.gov. (n.d.). Preventative and screening services.
Medicare.gov. (n.d.). Special enrollment periods.
Medicare.gov. (n.d.). When does Medicare coverage start?
Medicare.gov. (n.d.). Yearly “wellness” visits.
U.S. Department of Health and Human Services. (2014). What does Part B of Medicare (medical insurance) cover?
U.S. Social Security Administration. (n.d.). Sign up for Medicare.
