Medicare Part B covers outpatient medical services, preventive care, durable medical equipment, and a limited set of prescription drugs. In 2025, the standard monthly premium is $185.00, with an annual deductible of $257. After you meet that deductible, you typically pay 20% of the Medicare-approved amount for most covered services.
Part B is one half of Original Medicare (Part A handles hospital stays). It picks up the costs you’d encounter outside a hospital: doctor visits, lab work, screenings, mental health care, medically necessary equipment, and ambulance rides. Here’s how it breaks down.
Doctor Visits and Outpatient Care
Part B covers medically necessary services, defined as services or supplies that meet accepted standards of medical practice to diagnose or treat a medical condition. In practical terms, this means your visits to primary care doctors, specialists, and outpatient hospital departments are covered. If your doctor orders lab tests, X-rays, or other diagnostic work during those visits, Part B pays for that too.
After your $257 annual deductible, you’re responsible for 20% of the Medicare-approved amount. So if a specialist visit is approved at $200, you’d pay $40 out of pocket.
Preventive Services at No Cost
One of Part B’s strongest features is its preventive care coverage. You pay nothing for most preventive services as long as your provider accepts Medicare assignment. These aren’t subject to the deductible or the 20% coinsurance.
Covered preventive services include:
- Cancer screenings: mammograms, colonoscopies, lung cancer screenings with low-dose CT, cervical and vaginal cancer screenings, prostate cancer screenings, and colorectal options like stool DNA tests and fecal occult blood tests
- Cardiovascular screenings: cholesterol and lipid level checks, plus behavioral therapy for heart disease risk
- Diabetes care: diabetes screenings, self-management training, medical nutrition therapy, and a Diabetes Prevention Program
- Vaccines: flu shots, COVID-19 vaccines, pneumococcal shots, and hepatitis B shots
- Other screenings: depression, glaucoma, hepatitis B and C, HIV, bone density, alcohol misuse, and sexually transmitted infections
- Counseling: tobacco cessation counseling and obesity behavioral therapy
Part B also covers two important wellness visits. The first is a one-time “Welcome to Medicare” preventive visit, available within your first 12 months of enrollment. After that, you’re eligible for a yearly wellness visit where your doctor reviews your health, updates your prevention plan, and screens for cognitive changes. Neither visit costs you anything.
Mental Health Coverage
Part B covers outpatient mental health care, including psychiatric evaluations, individual and group psychotherapy, and medication management visits. You can receive these services from doctors and certain other licensed mental health professionals, depending on your state’s rules.
Your annual depression screening is covered at no cost when performed in a primary care setting that can provide follow-up treatment or referrals. Beyond that free screening, you pay 20% of the Medicare-approved amount for mental health visits after meeting your deductible.
Durable Medical Equipment
Part B covers durable medical equipment (DME), which Medicare defines as equipment that can withstand repeated use, serves a medical purpose, is typically useful only to someone who is sick or injured, is used in your home, and is expected to last at least three years.
Covered equipment includes:
- Wheelchairs, scooters, walkers, canes, and crutches
- Hospital beds
- Oxygen equipment and accessories
- CPAP machines for sleep apnea
- Blood sugar monitors, test strips, lancets, and control solutions
- Infusion pumps and supplies
- Commode chairs
- Respiratory assist devices
You’ll generally pay 20% of the Medicare-approved amount for DME. Your equipment must be ordered by a Medicare-enrolled doctor or provider, and in many cases you need to use a Medicare-approved supplier.
Prescription Drugs Under Part B
Most prescription drugs fall under Part D (the separate drug plan), but Part B covers a specific category: drugs you wouldn’t normally give yourself at home. These are typically injections or infusions administered in a doctor’s office or outpatient setting.
Part B drug coverage includes:
- Most injectable and infused drugs given by a licensed medical provider
- Drugs delivered through DME, like medications used with a nebulizer or infusion pump
- Certain oral cancer drugs when an injectable version of the same drug exists
- Anti-nausea drugs taken within 48 hours of chemotherapy
- Injectable osteoporosis drugs
- HIV prevention drugs (PrEP)
- Blood clotting factors for hemophilia
- Immunosuppressive drugs after a Medicare-covered organ transplant
- Tube feeding and intravenous nutrition when you can’t absorb food normally
- Intravenous immune globulin for primary immune deficiency (including home administration)
All four major vaccines (flu, COVID-19, pneumococcal, and hepatitis B) are also covered under Part B, not Part D, which means they come at no cost to you.
Ambulance Services
Part B covers ground ambulance transportation when traveling by any other vehicle could endanger your health. Coverage applies for transport to the nearest appropriate facility that can treat your condition, whether that’s a hospital, critical access hospital, rural emergency hospital, or skilled nursing facility.
Air ambulance transport by helicopter or airplane is covered when you need immediate, rapid transport that a ground ambulance can’t provide. Non-emergency ambulance rides can also be covered, but you need a written order from your doctor confirming the medical necessity. If the ambulance company thinks Medicare might not pay for a non-emergency trip, they’re required to give you an advance notice before transport so you understand you may be responsible for the cost.
What Part B Does Not Cover
Several common health expenses fall outside Part B entirely. The biggest gaps catch many people off guard:
- Dental care: routine cleanings, fillings, tooth extractions, and dentures are not covered in most cases
- Vision: eye exams for prescription glasses and the glasses themselves are excluded
- Hearing aids: hearing aids and the exams to fit them are not covered
- Long-term care: custodial care in a nursing home or assisted living facility is not a Part B benefit
- Cosmetic surgery: procedures that aren’t medically necessary are excluded
- Routine physical exams: standard physicals are not covered (though the annual wellness visit is, which confuses many people)
- Massage therapy
Many people fill these gaps with a Medicare Supplement (Medigap) plan for cost-sharing, or a Medicare Advantage plan that bundles additional dental, vision, and hearing benefits.
What Part B Costs in 2025
The standard Part B premium for 2025 is $185.00 per month, deducted automatically from your Social Security check. Your annual deductible is $257, and after that you pay 20% coinsurance on most services. Preventive services are the exception: they’re covered at 100% with no deductible and no coinsurance.
If your income is higher, you may pay more. Medicare uses your tax return from two years prior to determine whether you owe an income-related monthly adjustment on top of the standard premium. This surcharge applies at several income tiers and can significantly increase your monthly cost.
Enrollment Timing and Penalties
Your initial enrollment period for Part B starts three months before the month you turn 65 and ends three months after that month, giving you a seven-month window. If you miss it and don’t qualify for a special enrollment period (typically because you had employer coverage), you’ll have to wait for the general enrollment period that runs January through March each year, with coverage starting July 1.
Delaying enrollment without qualifying coverage triggers a late enrollment penalty: your monthly premium increases by 10% for each full 12-month period you could have had Part B but didn’t sign up. That penalty is permanent, added to your premium for as long as you have Part B.