Medicare Part B: Cost, Coverage and Eligibility
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Medicare Part B covers outpatient care like doctor’s office visits, preventive care, scans and tests.
Most people pay a Medicare Part B premium of $185 per month in 2025.
It’s important to sign up for Part B when you become eligible for Medicare to avoid late enrollment penalties.
If you sign up for Medicare Advantage, you still pay a Part B premium.
Medicare Part B is the part of Medicare that covers most doctor visits and other outpatient medical services. It also covers durable medical equipment and preventive services.
How much does Medicare Part B cost?
Medicare Part B premiums
Most people pay the standard Medicare Part B monthly premium: $185 per month in 2025. 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
High-income beneficiaries may pay higher premiums for Medicare Part B. If your modified adjusted gross income from two years ago is above a certain threshold, you also need to pay an income-related monthly adjustment amount, or 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 deductibles and coinsurance
Medicare Part B comes with an annual deductible: $257 in 2025.
After you meet the deductible for the year, you typically pay 20% of the Medicare-approved amount for doctor services and other Medicare benefits. Medicare Part B pays the other 80%.
Your costs are limited to that 20% coinsurance if your doctor or other provider accepts the amount Medicare agrees to pay for the service. Some providers who charge more than the Medicare-assigned amount may bill patients for the difference. Always ask a new health care provider if they accept the amount Medicare pays.
Many Original Medicare enrollees purchase Medicare Supplement Insurance, also called Medigap, to help pay the out-of-pocket costs associated with Medicare Part B.
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What does Medicare Part B cover?
Medicare Part B generally covers care and services delivered at clinics or other outpatient locations. It's part of Original Medicare, along with Medicare Part A, which generally covers care at hospitals and skilled nursing facilities.
Medicare Part B coverage
Medicare Part B covers two kinds of services: medically necessary outpatient care and preventive services.
Medically necessary outpatient care
Medicare Part B covers a variety of outpatient care and services when they’re medically necessary. According to the Centers for Medicare & Medicaid Services (CMS), medically necessary services are “services or supplies that are needed to diagnose or treat your medical condition and that meet accepted standards of medical practice.”
Here are some examples of medically necessary services covered by Medicare Part B:
Outpatient services like visits to a health care provider at an office or clinic and services such as X-rays, stitches and casts that you get at a hospital without being admitted as an inpatient.
Durable medical equipment like CPAP machines, lift chair mechanisms, wheelchairs, canes, walkers, diabetes supplies and hospital beds, if they’re medically necessary and prescribed by your doctor.
Ambulance services to the nearest appropriate medical facility to get medically necessary care, if traveling in any other vehicle could endanger your health.
Prescription drugs you don’t give yourself, like infusions or injections you have to get at a doctor’s office or hospital outpatient department. (Most prescription drugs, which you take yourself, are covered by Medicare Part D or Medicare Advantage plans that include prescription drug coverage instead.)
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.)
Preventive services
Medicare Part B also covers preventive care and services, including certain disease and cancer screenings, tests, shots and counseling. While most medically necessary services require a 20% Part B coinsurance, you don’t pay anything for most preventive services.
Here are a few examples of preventive services for which you’ll pay nothing under Medicare Part B:
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. You can find specific details for how individual services are covered at medicare.gov/coverage.
What does Medicare Part B not 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.
Medicare Part B eligibility
You become eligible for Medicare Part B at age 65 and should sign up for Medicare during the initial enrollment period, 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 automatically start receiving Original Medicare — Part A and Part B — the month you turn 65.
Everyone else must choose among these enrollment period options:
Initial enrollment period: This is the seven-month period starting three months before the month you turn 65, including your birthday month and ending 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, such as leaving a job or moving out of your plan’s coverage area.
General enrollment period: This runs from Jan. 1 through March 31 every year and is the time when people who are already receiving Medicare benefits 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 at age 65 when you become eligible and later change your mind, you’ll pay an extra 10% above the standard premium cost for every 12-month period you delayed. And you’ll pay this late enrollment penalty permanently.
💬 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 choose to have both Medicare Part B and employer insurance, or you can choose to delay enrolling in Part B while you’re covered by the employer plan.
If you choose not to sign up for Medicare Part B right away and you’re covered by employer-sponsored insurance (yours or your spouse’s) from a company with 20 or more employees, you won’t need to pay the Part B late enrollment penalty. In those cases, unless you’re already receiving Social Security or Railroad Retirement Board benefits, you don’t have to do anything when you turn 65. (If you’re receiving Social Security or those benefits, and you want to delay Medicare Part B, follow the instructions that come with the Medicare card you’ll receive near your 65th birthday or call Social Security at 800-772-1213.)
If you decide to stick with employer-sponsored coverage without signing up for Medicare Part B, make sure you know when your coverage will end, as you’ll need to take action at that time. You have eight months to sign up for Part B before incurring the penalty.
If you sign up for Medicare Part B and keep your employer insurance, both of them can pay for your covered medical bills. Which coverage applies first depends on your plan and your employer, so check with your plan for information on how it coordinates with Medicare.
Do I need both Medicare Parts A and B?
If you don’t qualify to get Medicare Part A for free, you can buy Part B on its own, as long as you’re eligible. If you want to buy a Medicare Advantage plan or a separate Medicare Part D prescription drug plan, you’ll need both Medicare Parts A and B.
Note that if you’re not eligible for premium-free Part A, you don’t have to purchase it — but if you sign up after your initial enrollment period, you may have to pay a late penalty.
Does everyone pay for Medicare Part B?
Medicare Part B has a monthly premium, but if you have a low income and qualify for a Medicare Savings Program, you may be able to get help covering Part B costs. Some Medicare Advantage plans also cover a portion of the Part B premium.
Can I keep my doctor on Medicare Part B?
If you have health care coverage through Medicare Part B (medical insurance), you can see any health care provider who accepts Medicare and who is accepting new Medicare patients. You’ll want to ask your doctor if they can take you as a new Medicare patient.
That said, not all providers accept Medicare as full payment. Medicare classifies health care providers three ways:
Participating: They accept Medicare and Medicare approved payment for services.
Nonparticipating: They accept Medicare but may charge more than Medicare’s approved payment for services.
Opt-out: They don’t accept Medicare at all, and patients are responsible for all costs for care, except for emergency care or urgently needed care.
Does Medicare Part B cover prescriptions?
Medicare Part B covers some prescription drugs, but not the ones you get at the pharmacy. Part B’s coverage applies to inpatient medicine, like a flu vaccine you get at your primary care physician. Medicare Part B also covers some oral cancer drugs and medicines you’d have to use with durable medical equipment, such as nebulizer medications. And on rare occasions, Part B covers drugs you’re given in a hospital outpatient situation.
Is Medicare Part B mandatory?
You’re not required to have Medicare Part B, although you must have Part A and Part B to buy a Medicare Advantage or Part D plan. If you wait too long to enroll in Part B after you’re eligible, you could pay a permanent late penalty.
The parts of Medicare
Read more about the different parts of Medicare and what they cover.
