Medicare Part B Explained

What is Medicare Part B?

Medicare Part B is sometimes called “medical insurance.” It covers doctor’s office visits and labs, x-rays, outpatient, and preventive services not covered by Part A. Most people pay a monthly premium for Part B. Medicare Part B is optional—but if you do not sign up when you are first eligible, you may have to pay a late enrollment penalty.

What does Medicare Part B cover?

Medicare Part B coverage is split into two categories: medically necessary services and preventive services. The Centers for Medicare & Medicaid Services (CMS) describes medically necessary services as “services or supplies needed to diagnose or treat your medical condition and that meet accepted standards of medical practice.”

Medically necessary services

• Doctor and other health care provider services like outpatient services, office visits, and consultations. This includes getting stitches or a cast, or any visit where you are not admitted as an inpatient.
• Outpatient surgery, meaning minor surgeries and services received in a hospital outpatient department or clinic where you are not admitted for an inpatient stay. 
• Lab and x-ray services that include a wide range of clinical lab tests to diagnose and treat medical conditions under Medicare Part B. Diagnostic imaging services like x-rays, CT scans, and PET scans are covered when medically necessary.
• Ambulance services, meaning transportation to the nearest medical facility when other transportation could endanger your health.
• Outpatient mental health services including counseling, psychotherapy, and some prescriptions for mental health conditions.
• Some prescription drugs, like chemotherapy and injectable medications, that you would receive in a doctor’s office or outpatient facility.
• Durable medical equipment like prosthetics, wheelchairs, and hospital beds prescribed for use in your home.

Preventive services

• Screenings for conditions such as cancer, diabetes, cardiovascular disease, and more.
• Vaccines like influenza, pneumococcal infections, hepatitis B (for individuals at high risk), and COVID-19.
• Nutrition therapy services provided by a registered dietitian or other qualified nutrition professional. This may include counseling for chronic conditions like obesity, hypertension, or cardiovascular disease if prescribed by a healthcare provider. 
• Counseling services for smoking cessation, obesity, alcohol dependency, depression, and other behavioral health issues.
• Outpatient mental health services like individual or group therapy sessions with a qualified mental health professional, diagnostic assessments to diagnose mental health conditions, depression screenings, substance abuse treatment, family counseling, and more.
• Yearly wellness visits: one visit every 12 months. The visit will include a medical history review, risk factors, and a personalized prevention plan.

Preventive care helps you stay healthier by catching potential issues early and supporting your well-being. Medicare Part B covers a range of services designed to help you take a proactive approach to your health.

Not sure if your service or product is covered? Find out what Medicare covers.

What does Medicare Part B not cover?

Part B does not cover any of the following items or services:

• Routine hearing, dental, and vision exams
• Hearing aids or glasses (except for glasses after cataract surgery)
• Emergency assistance while traveling outside the U.S.
• Fitness club membership
• Long-term care (such as a nursing home)
• Most prescription drugs

Medicare Part B costs in 2026

Part B requires you to pay a monthly premium, calculated based on your adjusted gross income, along with a yearly deductible before coverage begins. You are also responsible for paying part of the costs that Part B does not cover. In 2026, the standard monthly premium is $202.90, and the standard yearly deductible for 2026 is $283.

Your costs include:

• Your Medicare Part B monthly premium, if applicable.
• A yearly deductible (paid before Medicare begins paying).
• Coinsurance (percentage of the cost that Medicare does not pay).

Learn more about 2026 Medicare Parts A & B premiums and deductibles.

Medicare Part B premium for 2026

The standard premium for Medicare Part B in 2026 is $202.90. This is what most people will pay each month for their Part B coverage. This amount can either be taken out of your monthly Social Security check or you can pay Medicare directly. If you earn above a certain amount, you may have to pay more each month. This extra amount is called Income-Related Monthly Adjustment Amount (IRMAA).

IRMAA is based on your reported income from two years ago. This means in 2026, Medicare looks at your 2024 tax return to determine if you owe more than the standard premium. The more you earn, the higher your monthly premium will be.

Medicare Part B deductible for 2026

In addition to your monthly premium, you will also have to pay a yearly deductible before Medicare starts to pay for its share of the costs for care. In 2026, the annual deductible is $283. This means you must pay the first $283 for Medicare-covered services out-of-pocket each year. Once you meet this deductible, Medicare typically pays 80 percent of approved costs, and you pay the remaining 20 percent.

Can I get Medicare Part B for free?

Medicare Part B is free for low-income individuals enrolled in a Medicare savings program. This helps pay for premiums, deductibles, coinsurance, and copays. To qualify, individuals must meet specific income requirements. These requirements are updated yearly based on federal poverty level guidelines.

Visit Medicare Savings Programs to see if you qualify. 

Medicare Part B eligibility requirements

You can enroll in Medicare Part B if:
• You are age 65 or older.
• You are under age 65 with certain disabilities.
• You have permanent kidney failure requiring dialysis.

How to enroll in Medicare Part B

If you already get benefits from Social Security, you'll get Medicare Parts A and B automatically when you're first eligible and don't need to sign up. Medicare will send you a "Welcome to Medicare" packet three months before you turn 65. You can also contact the Social Security Administration to sign up for Original Medicare. Go to SSA.gov or call 1-800-772-1213 Monday through Friday from 8 a.m. to 7 p.m. TTY users should call 1-800-325-0778.

1. Check if you are automatically enrolled. If you already receive Social Security benefits, you will typically be automatically enrolled in Medicare Parts A and B when you become eligible.
2. Look for your “Welcome to Medicare” packet. Medicare will mail this packet three months before your 65th birthday. It includes important information about your coverage and enrollment options.
3. Sign up manually if needed. If you are not automatically enrolled, you must contact the Social Security Administration (SSA) to sign up for Part B.
4. Apply online. Go to SSA.gov and complete the Medicare enrollment application.
5. Apply by phone. Call Social Security at 1-800-772-1213 (TTY: 1-800-325-0778) Monday through Friday from 8 a.m. to 7 p.m. to enroll by phone or ask questions.
6. Apply in person: Visit your local Social Security office to complete the application in person if you prefer face-to-face.
7. Confirm your enrollment. After you sign up, you will receive your Medicare card showing your Part A and Part B start dates.

When can you enroll to avoid penalties?

You can enroll in Medicare Part B during your Initial Enrollment Period. This starts three months before you turn 65, includes your birthday month, and ends three months after your birthday month.

If you or your spouse is still working at 65 and has employer coverage, you may be able to delay enrolling in Part B until you retire or lose your employer coverage. You will then have an eight-month Special Enrollment Period (SEP) to sign up without penalty.

If you do not sign up when you are first eligible or during your SEP after retiring, you may face late enrollment penalties. You will pay an extra 10 percent for each year you didn’t sign up, and this is a lifetime penalty.

Frequently asked questions about Medicare Part B

Is Medicare Part B required?

Medicare Part B is voluntary, but you will need it to cover doctor visits and outpatient care. If you don’t sign up for Part B when you’re eligible, you will pay penalties later unless you have other creditable coverage, such as employer insurance plan.

Can you delay Part B if you’re still working?

Possibly. If you or your spouse is still working past 65 and your employer has more than 20 employees, you can stay on your employer’s health plan and don’t need to sign up for Part B right away. If your employer has fewer than 20 employees, you may need to sign up for Medicare when you turn 65. It’s important to confirm with your employer whether your current plan counts as creditable coverage (equal to or better than Medicare).

Does Part B cover prescriptions?

Medicare Part B covers a limited number of outpatient prescription drugs and some vaccines. These drugs are typically ones that you can’t give yourself, like those given through infusion pumps or nebulizers, and must be administered in a doctor’s office or outpatient facility. Most prescription drugs are covered under Medicare Part D, so you will need to enroll in standalone Part D plan or a Medicare Advantage plan that includes drug coverage.