Medicare Part B: Cost, Coverage and Eligibility
Medicare Part B covers medically necessary outpatient services and preventive care for people 65+ and those under 65 with a disability or specific health condition.
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Medicare Part B overview
Medicare Part B is the medical insurance part of Medicare. It covers care you get at clinics and other outpatient locations. It's part of Original Medicare, along with Medicare Part A, which is hospital insurance.
Doctor visits.
Outpatient services.
Home health care.
Durable medical equipment.
Vaccines.
Lab tests and screenings.
What does Medicare Part B cover?
Medicare Part B covers medically necessary outpatient care and preventive services. Most medically necessary services require a 20% Part B coinsurance, but you don’t pay anything for most preventive services.
Medicare Part B covers the following medically necessary services:
Doctor’s office visits, emergency room visits and specialist visits.
Outpatient hospital services like X-rays, stitches and casts.
Durable medical equipment like CPAP machines, lift chair mechanisms, wheelchairs, canes, walkers, diabetes supplies and hospital beds.
Ambulance services if traveling in any other vehicle could endanger your health.
Prescription drugs that have to be administered at a doctor's office or hospital. These can include infusions or injections. (Prescription drugs you take on your own are covered by Medicare Part D.)
Mental health services like therapy or counseling, psychiatric evaluations, medication management and partial hospitalization for mental health issues. (Part A covers mental health care if you’re admitted as an inpatient.)
Medicare Part B also covers the following preventive services:
Certain disease and cancer screenings.
Exams, shots and lab tests.
COVID-19 vaccines and testing.
Flu shots.
Screening colonoscopies (you may need to pay coinsurance for additional services like polyp removal or barium enemas).
Certain preventive services are limited to certain sexes and/or have conditions on how often Medicare covers them. To pay nothing for some services, you need to get them from a health care provider that accepts Medicare assignment. Luckily, almost all do. You can find specific details for how individual services are covered at medicare.gov/coverage.
What Medicare Part B doesn't cover
There are some services Medicare Part B doesn’t cover. You’d be responsible for paying for these services out of pocket unless you have other insurance that covers them.
Here are a few examples of services not covered by Medicare Part B:
Most dental care and dentures.
Routine eye exams (unless you're at risk for certain conditions).
Care while traveling abroad (except under rare circumstances).
Cosmetic surgery.
How much does Medicare Part B cost?
Medicare Part B premiums
The Medicare Part B premium is $185 per month in 2025 for most people. Premium amounts usually change from year to year.
Part B premiums with Medicare Advantage
You’re still responsible for your Medicare Part B premium even if you choose a Medicare Advantage plan. However, some Medicare Advantage plans will pay for some or all of your Part B premiums.
To see whether a Medicare Advantage plan will pay for some or all of your Part B premium, look for plans with “Part B premium reduction” or “Giveback” benefits.
Medicare Part B premiums for members with high income
People with high incomes may have to pay a higher Medicare Part B premium. This is known as the income-related monthly adjustment amount, or IRMAA. The government looks at your modified adjusted gross income from two years ago to determine whether you have to pay the IRMAA.
For 2025, beneficiaries whose 2023 income exceeded $106,000 (individual return) or $212,000 (joint return) will pay a premium amount ranging from $259 to $628.90, depending on income.
Medicare Part B deductible
Medicare Part B comes with an annual deductible of $257 in 2025. You must pay this much each year before Medicare Part B starts to pay.
Medicare Part B coinsurance
After you meet the deductible for the year, you usually pay a 20% coinsurance for covered services. Medicare Part B pays the other 80%.
This is true if your provider accepts the amount Medicare agrees to pay for the service. Some providers charge more than the Medicare-assigned amount. They may bill patients for the difference. Always ask a new health care provider if they accept the amount Medicare pays.
Many people on Original Medicare buy a Medigap plan. This supplemental insurance helps cover these out-of-pocket costs.
Medicare Part B eligibility
You become eligible for Medicare Part B at age 65. You should sign up for Medicare during your initial enrollment period, which is the seven-month period around your birthday. People can also become eligible for Medicare based on disability before age 65.
How to enroll in Medicare Part B
Most people start getting Medicare Part B at age 65. If you’re already receiving Social Security or Railroad Retirement Board benefits, you’ll be automatically enrolled in Original Medicare when you turn 65.
Everyone else must choose among these enrollment period options:
Initial enrollment period: This seven-month period starts three months before the month you turn 65. It includes your birthday month and ends three months after your birthday month. So if you turn 65 in July, you’ll have from April 1 to Oct. 31 to enroll.
Special enrollment period: This is when you’re allowed to join Medicare or make changes to your coverage based on specific life events. These include leaving a job or moving out of your plan’s coverage area.
General enrollment period: This period runs from Jan. 1 through March 31 every year. It's when people who already have Medicare can make limited changes to their coverage. It’s also when people who miss the deadline for initial enrollment can sign up.
Note: You still need to sign up for Medicare Part B if you’re receiving health care continuation coverage under COBRA. Otherwise, you’ll pay the Part B penalty. COBRA beneficiaries aren't eligible for the special enrollment period. In other words, COBRA isn't the same as if you were covered under a large employer health plan.
Medicare Part B late enrollment penalty
If you don't sign up for Part B when you become eligible at age 65 and later change your mind, you’ll pay a permanent late enrollment penalty. The penalty is an extra 10% above the standard premium cost for every 12-month period you delayed.
💬 From our Nerds: Can you add Medicare Part B at any time?
“You should generally sign up for Part B during your initial enrollment period around your 65th birthday, unless you have group health insurance from an employer with 20 or more employees. Once that employer coverage ends, you have eight months to sign up for Part B.
“If you aren’t covered by qualifying group health insurance and you miss your enrollment windows, you may pay a late enrollment penalty for Part B — and you’ll pay it for as long as you have Part B.”
— Kate Ashford, lead writer covering Medicare
How does Medicare Part B work with employer insurance?
You can have both Medicare Part B and employer insurance at the same time, or you can delay enrolling in Part B.
If you decide to have both insurances, they work together to pay for your covered medical bills. If you decide to delay enrolling in Part B, you can avoid late enrollment penalties as long as:
You're covered by your or your spouse's employer-sponsored insurance.
The employer has 20 or more employees.
You sign up for Part B within eight months of your coverage ending.
You don’t have to do anything to delay enrollment, unless you’re already receiving Social Security or Railroad Retirement Board benefits before you turn 65. If this is the case, you’ll receive a Medicare card in the mail near your 65th birthday. Follow the instructions that come with the card. You can also call Social Security at 800-772-1213.
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