There are already separate guides to Medicare Part A and Part D, but Part B — your outpatient medical insurance — is the piece most people use most often and the one that raises the most questions about cost. This guide explains in detail what Part B covers, how its premium and high-income surcharge work, when to enroll, and how it pairs with Medicare Advantage or Medigap if you live in Orange, Los Angeles, San Diego, or Riverside County.
What Part B actually covers
Part B covers the medical services you receive outside of a hospital stay: visits to your primary doctor and specialists, outpatient services at clinics and hospitals, physical and occupational therapy, outpatient mental health care, and durable medical equipment such as wheelchairs, walkers, supplemental oxygen, and home hospital beds.
It also includes a broad catalog of no-cost preventive care when the provider accepts Medicare assignment: the Welcome to Medicare visit, the annual wellness visit, flu and pneumonia vaccines, cancer screenings, diabetes and bone density testing, and depression screenings, among others. Taking advantage of these preventive benefits is one of the simplest ways to get real value out of your coverage.
The standard premium and the high-income IRMAA surcharge
Medicare sets a new standard monthly Part B premium every year, and for most people already receiving Social Security benefits, that premium is deducted automatically from their monthly payment. Because the exact figure changes annually, we always confirm the current amount for the year you are enrolling rather than assuming last year's number.
If your modified adjusted gross income (MAGI) exceeds certain thresholds — based on your tax return from two years earlier — you will pay an additional surcharge called IRMAA on top of the standard Part B premium, and on your Part D plan too if you have one. The surcharge applies in several tiered levels: the higher your income, the higher the tier and the additional amount.
One important point many people do not know: if your income dropped significantly due to a qualifying life event — retirement, reduced work hours, job loss, divorce, or the death of a spouse — you can ask Social Security to reconsider your IRMAA surcharge using more recent income instead of the return from two years earlier. It is worth filing that request if your situation changed.
Part B also covers telehealth services for medical and mental health visits when you qualify, ambulance transportation in medical emergencies, and a second medical opinion before non-emergency surgery, something many people do not realize is covered and that can help you make a more informed decision before a major procedure.
The annual Part B deductible
In addition to the monthly premium, Part B has an annual deductible that you pay out of pocket before Medicare begins covering its share of your covered services. Once you meet that deductible during the calendar year, you generally pay 20% coinsurance on the Medicare-approved amount for most Part B services, with no upper limit unless you have a Medigap policy or a Medicare Advantage plan that caps that spending.
That uncapped 20% is precisely why many people add a Medigap policy or choose a Medicare Advantage plan: without one or the other, a hospitalization or extended treatment can generate significant out-of-pocket costs under Original Medicare from the Part B side alone.
Availability, cost, benefits, and eligibility vary by person, product, contract, and insurance company, as well as by your service area. Guarantees are subject to the claims-paying ability of the issuing insurance company. Karla Arámburo is not affiliated with or endorsed by Medicare or the federal government.
Initial Enrollment Period vs. Special Enrollment Period
Your Initial Enrollment Period lasts seven months: it starts three months before the month you turn 65, includes your birthday month, and ends three months after. If you enroll during the first three months, coverage usually starts the first day of your birthday month; enrolling later in that window can delay when your coverage begins.
If you continue working actively past 65 with employer coverage from an employer with 20 or more employees that counts as creditable, you can delay Part B without a penalty. Once that coverage ends — through retirement or any other reason — you get an 8-month Special Enrollment Period to enroll in Part B without a penalty, with no need to wait for a general enrollment period.
The late enrollment penalty
If you do not enroll in Part B when first eligible and do not have creditable employer coverage justifying the delay, you will generally pay a permanent penalty: an additional 10% on top of the standard premium for each full 12-month period you could have had Part B but did not. That penalty is added to your monthly premium for as long as you have Medicare, not just for a limited time.
This penalty can surprise people who incorrectly assumed that individual marketplace coverage, a COBRA plan, or international insurance counted as creditable coverage for delaying Part B at no cost. Before declining Part B for any reason, it is worth confirming whether your current coverage actually counts as creditable under Medicare's rules.
How Part B combines with Medicare Advantage and Medigap
Part B is required to enroll in any Medicare Advantage plan: you continue paying your Part B premium in addition to any extra Advantage plan premium, and the plan replaces how your Part A and Part B benefits are administered, generally through a provider network. See our Medicare Advantage vs. Original Medicare guide to compare both paths in depth.
If you stay with Original Medicare, a Medigap policy can cover the deductible and the 20% coinsurance that Part B leaves behind, depending on the plan letter you choose. You can read the details in our Medigap guide, and review how it pairs with drug coverage in our Part D guide.
In practice, this means that choosing between staying on Original Medicare plus a Medigap policy, or switching to a Medicare Advantage plan, completely changes how your Part B works day to day: with Medigap you keep the freedom to see almost any doctor who accepts Medicare in any state, while with Advantage you are generally limited to a specific network in exchange for extra benefits and, in many cases, a lower monthly premium.
A bilingual, local resource in Southern California
Karla Arámburo is a bilingual, licensed insurance agent serving Orange, Los Angeles, San Diego, and Riverside counties, and comparing your Part B options with her costs nothing and comes with no pressure to enroll. You can call or text (619) 321-8733, review our guide on 2026 Medicare enrollment dates, or check local information if you live in Riverside or San Diego. This page is general education, not individualized advice or an enrollment recommendation.
Frequently asked questions
Is Part B mandatory?
It is not legally mandatory, but most people need it because it covers everyday doctor visits and outpatient services. If you decline it without other creditable coverage, you will generally pay a permanent penalty whenever you do decide to enroll.
What exactly is the IRMAA surcharge?
IRMAA (Income-Related Monthly Adjustment Amount) is an extra charge added on top of the standard Part B (and Part D) premium for people with higher income. It is calculated using your tax return from two years earlier and has several tiered levels: the higher your income, the higher the surcharge.
Can I appeal the IRMAA surcharge?
Yes. If your income dropped due to a qualifying life event — such as retirement, job loss, divorce, or the death of a spouse — you can ask Social Security to reconsider the surcharge using more recent income instead of the return from two years earlier.
How is the Part B premium typically paid?
For most people already receiving Social Security benefits, the Part B premium is automatically deducted from their monthly payment. If you are not yet receiving those benefits, Medicare bills you for the premium directly each quarter.
What happens if I keep working past 65 and have employer coverage?
If your employer has 20 or more employees and its coverage counts as creditable, you can delay Part B without penalty while that coverage continues. Once it ends, you get an 8-month Special Enrollment Period to sign up without a penalty.
Does Part B cover routine vision or dental exams?
No. Part B does not cover routine vision exams, eyeglasses, or routine dental care. Those benefits are usually included in a Medicare Advantage plan or purchased separately.
Can I have Part B alongside a Medicare Advantage plan?
Yes — in fact it is required: to enroll in any Medicare Advantage plan you need both Part A and Part B active, and you continue paying the Part B premium in addition to any Advantage plan premium.