Medicare Part B — outpatient coverage and the monthly premium reality

Reviewed by the How To Help Your Elders Team | Updated March 2026

Medicare Part B covers doctor visits, specialists, lab tests, imaging, preventive care, durable medical equipment, and mental health services. The standard monthly premium is approximately $185 in 2025, with higher-income earners paying more through IRMAA. After the annual deductible, your parent pays 20 percent of approved charges with no annual out-of-pocket cap.

Part B Is the Medicare Your Parent Uses Most, and the Costs Add Up

My mother's first shock with Medicare wasn't the coverage gaps. It was the monthly bill. She'd been told Medicare was "free" because she paid into it her whole life. Then the letters came showing a monthly Part B premium coming out of her Social Security, and she kept asking me, "But I already paid for this. Why am I paying again?" That question revealed something important: most people don't understand that Part B isn't free, what they're paying for, or what happens if the costs keep climbing.

Part A covers hospital stays. Part B covers everything that happens outside the hospital: doctor visits, specialists, labs, imaging, preventive care. It's actually the part of Medicare your parent will use more often, because they'll have doctor visits far more frequently than hospital stays. But because it's something they interact with regularly, the costs add up faster than they expect.

Understanding Part B means understanding premiums, deductibles, copays, and a 20 percent share of costs that never goes away. Unlike some insurance plans, Part B has no annual out-of-pocket maximum. Your parent could theoretically keep paying their 20 percent forever, with no cap. For someone with multiple chronic conditions who sees lots of specialists, this is a genuine financial problem worth planning for.

What's Covered Under Part B

Medicare Part B covers the services your parent's doctors provide. Primary care visits, specialist visits (cardiologist, pulmonologist, orthopedist, and others), lab tests, diagnostic imaging including X-rays, ultrasounds, CT scans, MRIs, and PET scans are all covered. These are expensive services that would be unaffordable without insurance.

Durable medical equipment is covered. If your parent needs a wheelchair, walker, cane, hospital bed, oxygen, CPAP machine, or similar equipment, Part B pays for it after the deductible. A good wheelchair can cost thousands of dollars. Without coverage, that cost would be out of reach for many families.

Mental health services are covered. Therapy, counseling, and psychiatric care fall under Part B. This matters because mental health is often as important as physical health as people age, and having coverage removes one barrier to getting help.

Preventive services are covered at 100 percent, with no copay and no deductible. According to Medicare.gov, covered preventive services include the annual wellness visit, flu shots, pneumonia shots, COVID vaccines, colorectal cancer screening, mammography, cardiovascular screening, diabetes screening, depression screening, and various other screenings. This is a genuinely good deal. Catching problems early is cheaper than treating advanced disease, and your parent pays nothing for these services.

The Cost Structure You Need to Understand

Part B has a monthly premium that comes out of your parent's Social Security check automatically. According to CMS, the standard Part B premium for 2025 is $185 per month. This amount is adjusted every year.

The premium is higher for higher-income earners through something called IRMAA, which stands for Income-Related Monthly Adjustment Amount. According to CMS, a single person with modified adjusted gross income over $106,000 (or a couple over $212,000) pays a higher Part B premium. The rates increase with income level. If your parent is in a high-income year, maybe they took a large IRA distribution or sold property, their Part B premium can jump from $185 to $500 or more per month.

People don't plan for this. They don't realize that their financial moves can affect their Medicare premiums. Then they get the letter saying their premium is significantly higher, and they're blindsided. IRMAA is based on tax returns from two years prior, so a large income event in 2024 affects 2026 premiums.

Part B also has an annual deductible. According to CMS, the Part B deductible for 2025 is $257. Once your parent pays this deductible, Medicare starts covering services. After the deductible is met, your parent pays 20 percent of Medicare's approved amount for most services. Medicare pays 80 percent.

The percentages matter less than understanding that there's no cap. If your parent has a chronic condition requiring frequent specialist visits and expensive treatments, they're paying 20 percent of all those costs with no annual maximum. Someone with cancer getting chemotherapy, someone with kidney disease seeing a nephrologist every month, someone with congestive heart failure seeing a cardiologist quarterly, all of these people can accumulate substantial out-of-pocket costs. According to KFF, about a quarter of Medicare beneficiaries spend 20 percent or more of their income on healthcare.

The Uncapped 20 Percent That Breaks Budgets

This is the part that actually worries people who understand insurance. Part B has no out-of-pocket maximum. Your parent pays 20 percent of their healthcare costs for as long as they receive services, and there's no threshold where Medicare says "that's enough, we're covering it all now."

Other insurance plans typically have an out-of-pocket maximum. Once someone hits that number, the insurance covers everything else. Not Medicare Part B. The 20 percent exposure is unlimited.

This doesn't happen to most people. Most people have relatively healthy aging. They see their doctor once or twice a year, get labs done, take preventive care seriously, and their Part B costs are manageable. But for someone with serious illness, it's a real problem.

This is why Medigap insurance exists. Medigap is supplemental insurance that fills the gaps Medicare leaves behind. A Medigap policy covers the deductible, the 20 percent copays, and other out-of-pocket costs you'd face with Original Medicare. With the right Medigap plan, your parent never pays the 20 percent.

Medigap premiums run from about $100 to $300 or more per month depending on the plan, your parent's age, and location. But if your parent has chronic conditions and sees lots of specialists, it's often cheaper than paying 20 percent of everything. According to KFF, about 23 percent of Original Medicare beneficiaries have a Medigap policy.

Making Part B Work for Your Parent

The first thing is to use the preventive benefits. These are covered at 100 percent. Annual wellness visits, cancer screenings, heart disease screenings, diabetes screenings: your parent should do them. They're free. They catch problems early when they're cheaper to treat and easier to manage.

Second, your parent should confirm that their doctors accept Medicare. Not all doctors do. Some opt out of Medicare entirely and require private pay. Your parent should know this before making an appointment, not find out afterward that the doctor doesn't accept Medicare and they owe the full fee. According to CMS, the vast majority of physicians participate in Medicare, but a small percentage have opted out.

Third, if Part B costs are genuinely a problem because of chronic illness, Medigap insurance can help. There are different Medigap plans (Plan A through Plan N) with different coverage levels and costs. Plan G is popular because it covers most of the gaps. The critical timing: your parent needs to enroll in Medigap within six months of enrolling in Part B for guaranteed-issue rights. According to Medicare.gov, during this six-month Medigap open enrollment period, insurance companies cannot deny coverage or charge more based on pre-existing conditions. If they wait longer, companies can charge more or deny them.

Fourth, if Part B denies a claim, your parent can appeal. Sometimes Medicare determines something isn't medically necessary or isn't a covered service. Your parent's doctor can provide documentation explaining why it is necessary. The appeal process takes time, but it's worth trying if the claim amount is significant.

The Reality of Aging and Specialists

Part B is the insurance your parent will interact with most, because aging means specialists. The primary care doctor might recommend a cardiologist for blood pressure. The cardiologist might recommend an echocardiogram. Then a gastroenterologist for heartburn, an ophthalmologist for cataracts, a rheumatologist for arthritis. Each specialist visit is covered by Part B. Each test is covered. Each adds to that 20 percent out-of-pocket total.

None of this is surprising or unusual. It's normal aging. But normal aging is expensive, and Part B without supplemental coverage means your parent is paying 20 percent of all of it.

Understanding Part B upfront means your parent can plan for these costs. They can decide whether to get Medigap insurance. They can understand their premiums before they arrive. They can make decisions about their healthcare with their eyes open instead of finding out later what things cost.

Your parent spent decades paying Medicare taxes. Part B is what they get in return. It's substantial coverage. But like most things worth having, understanding the costs and planning for them makes the experience less stressful when your parent actually needs to use it.

Frequently Asked Questions

How much is the Part B premium?
The standard Part B premium in 2025 is $185 per month. It's deducted automatically from Social Security. Higher-income earners pay more through IRMAA. The premium is adjusted annually.

What is IRMAA, and how does it affect my parent?
IRMAA stands for Income-Related Monthly Adjustment Amount. If your parent's modified adjusted gross income exceeds certain thresholds (about $106,000 for individuals or $212,000 for couples in 2025), they pay a higher Part B premium. IRMAA is calculated based on the tax return from two years prior. A one-time income spike, such as selling a property, can trigger a higher premium. Your parent can appeal if income has since dropped due to a life-changing event like retirement.

Does Part B have an out-of-pocket maximum?
No. This is one of the most significant differences between Medicare and most private insurance. Under Part B, your parent pays 20 percent of the approved amount for covered services with no annual cap. This is why many people buy Medigap supplemental insurance.

What preventive services does Part B cover for free?
Part B covers the annual wellness visit, flu shots, pneumonia shots, COVID vaccines, mammography, colorectal cancer screening, cardiovascular screening, diabetes screening, depression screening, bone density tests, and other preventive services at no cost. No copay, no deductible. Your parent should use these.

When should my parent sign up for Medigap?
The best time is during the six-month Medigap open enrollment period, which starts the month your parent turns 65 and is enrolled in Part B. During this window, insurance companies cannot deny coverage or charge higher premiums based on health status. After this window closes, companies can use medical underwriting, meaning they can charge more or deny coverage based on pre-existing conditions.

Can my parent appeal a Part B claim denial?
Yes. If Medicare denies a claim as not medically necessary or not covered, your parent or their doctor can appeal. The first level of appeal is a redetermination by the Medicare Administrative Contractor. If that fails, there are additional appeal levels. The process takes time but is free and worth pursuing for significant charges.