Medicare Part B 2026: Coverage, Costs, and Enrollment

A comprehensive guide to Medicare Part B — what it covers, what it costs, when to enroll, and how to avoid expensive late enrollment penalties.

What Is Medicare Part B?

Medicare Part B is one of the four parts of the Medicare program, which provides health insurance to Americans aged 65 and older, as well as to certain younger people with disabilities and those with End-Stage Renal Disease (ESRD). Part B is often referred to as "medical insurance" because it covers services and supplies that are medically necessary to treat a health condition. This includes doctor visits, outpatient hospital care, preventive services, laboratory tests, X-rays, mental health services, and durable medical equipment such as wheelchairs, walkers, and oxygen equipment.

Part B is optional, but most people choose to enroll because it provides essential coverage that Original Medicare Part A (hospital insurance) does not. While Part A covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health care, Part B covers the wide range of outpatient services that most people need on a regular basis. Without Part B, you would be responsible for paying 100% of these costs out of pocket, which can be financially devastating for seniors on fixed incomes.

Part B is administered by the federal government through the Centers for Medicare and Medicaid Services (CMS). You can receive your Part B benefits either through Original Medicare, where the government pays healthcare providers directly, or through a Medicare Advantage Plan (Part C), which is offered by private insurance companies approved by Medicare. If you choose Original Medicare, you may also want to purchase a Medigap (Medicare Supplement Insurance) policy to help cover the out-of-pocket costs that Part B does not pay, such as copayments, coinsurance, and deductibles.

What Does Medicare Part B Cover?

Medicare Part B covers a broad range of medical services and supplies. The coverage is divided into two main categories: medically necessary services and preventive services. Medically necessary services are those that are needed to diagnose or treat a medical condition and that meet accepted standards of medical practice. This includes doctor visits (both in the office and in the hospital), outpatient surgery, emergency room visits, ambulance services, laboratory tests, X-rays and other imaging services, mental health services (including outpatient psychiatric care), and durable medical equipment.

Preventive services are those that help prevent illness or detect it at an early stage when treatment is most effective. Medicare Part B covers many preventive services at no cost to you, including an annual wellness visit, cardiovascular screening, cancer screenings (such as mammograms, Pap tests, and colorectal cancer screenings), diabetes screenings, bone density measurements, flu shots, pneumococcal shots, hepatitis B shots, and counseling for smoking and tobacco use. These preventive services are covered at 100% of the Medicare-approved amount when you see a provider who accepts assignment.

Part B also covers certain home health services, such as part-time skilled nursing care, physical therapy, occupational therapy, and speech-language pathology services, when they are ordered by a doctor and provided by a Medicare-certified home health agency. Additionally, Part B covers some prescription drugs that are administered in a doctor's office or outpatient setting, such as chemotherapy drugs, injectable drugs, and drugs used with durable medical equipment. However, most prescription drugs you take at home are covered under Medicare Part D, not Part B.

2026 Medicare Part B Premiums and Costs

The standard monthly premium for Medicare Part B in 2026 is $185 per person. This amount is deducted automatically from your Social Security, Railroad Retirement, or Office of Personnel Management benefit check. If you do not receive any of these benefits, you will receive a bill for your Part B premium every three months. The premium amount is the same for most people, but higher-income beneficiaries may pay more due to the Income-Related Monthly Adjustment Amount (IRMAA).

IRMAA is an additional amount that beneficiaries with higher incomes must pay on top of the standard Part B premium. For 2026, the IRMAA surcharges are based on your modified adjusted gross income (MAGI) from your 2024 tax return. If your MAGI is above certain thresholds, you will pay an additional amount ranging from $70 to $428 per month, depending on your income level. The income thresholds for 2026 are: $106,000 for single filers, $212,000 for married couples filing jointly, and $318,000 for married couples filing separately. If your income has decreased significantly since 2024 due to a life-changing event such as retirement, marriage, or divorce, you can appeal the IRMAA determination.

In addition to the monthly premium, Part B has an annual deductible of $260 for 2026. You must pay this deductible out of pocket before Medicare begins to pay its share of your covered services. After you meet the deductible, you typically pay 20% of the Medicare-approved amount for most services, while Medicare pays the remaining 80%. There is no out-of-pocket maximum under Original Medicare, which means your costs could be very high if you have a serious illness or require extensive medical care. This is one of the main reasons why many people choose to purchase a Medigap policy or enroll in a Medicare Advantage Plan.

When to Enroll in Medicare Part B

Understanding when to enroll in Medicare Part B is critical to avoiding late enrollment penalties that can increase your premium for life. Most people should enroll during their Initial Enrollment Period (IEP), which is a seven-month window that begins three months before the month you turn 65, includes the month you turn 65, and ends three months after the month you turn 65. For example, if you turn 65 in June, your IEP runs from March 1 through September 30.

If you are already receiving Social Security or Railroad Retirement benefits at least four months before you turn 65, you will be automatically enrolled in Medicare Part A and Part B. You will receive your Medicare card in the mail about three months before your 65th birthday. If you do not want Part B, you must follow the instructions that come with your card to decline coverage. If you are not receiving Social Security benefits, you must sign up for Part B during your IEP or during a Special Enrollment Period (SEP) if you qualify.

If you are still working and have health insurance through your employer or your spouse's employer when you turn 65, you may be able to delay enrolling in Part B without penalty. You would qualify for a Special Enrollment Period that begins when you or your spouse stops working or when the employer coverage ends, whichever comes first. You then have eight months to enroll in Part B without penalty. However, if you do not have creditable coverage through a current employer, you must enroll during your IEP to avoid the late enrollment penalty.

Medicare Part B Late Enrollment Penalty

The Medicare Part B late enrollment penalty is a permanent increase in your monthly premium that applies if you do not enroll in Part B when you are first eligible and you do not have creditable coverage through a current employer. The penalty is 10% of the standard Part B premium for each full 12-month period that you were eligible for Part B but did not enroll. This penalty is added to your monthly premium for as long as you have Part B.

For example, if you were eligible for Part B at age 65 but did not enroll until age 68, you would have a 30% penalty (10% for each of the three full 12-month periods you delayed). If the standard Part B premium is $185, your penalty would be $55.50 per month, making your total monthly premium $240.50. This penalty lasts for the rest of your life, which means it can add up to thousands of dollars over time. The penalty is designed to encourage people to enroll when they are first eligible, which helps keep the Medicare program financially stable.

There are some exceptions to the late enrollment penalty. If you delayed enrollment because you had creditable health coverage through a current employer (yours or your spouse's), you will not be subject to the penalty. You must enroll in Part B during your Special Enrollment Period to avoid the penalty. Additionally, if you qualify for Medicare due to a disability and are under age 65, you will not be subject to the late enrollment penalty if you enroll in Part B when you first become eligible. If you believe you were charged a penalty in error, you can appeal the decision by contacting the Social Security Administration.

Medicare Part B and Other Insurance

Many people have other health insurance in addition to Medicare Part B, and understanding how these coverages work together is essential for avoiding gaps in coverage and unexpected costs. If you have health insurance through a current employer (yours or your spouse's), that insurance is typically the primary payer and Medicare is the secondary payer. This means the employer plan pays first, and Medicare pays second for any remaining costs that the employer plan does not cover.

If you have retiree health insurance from a former employer, Medicare is the primary payer and the retiree plan is the secondary payer. Retiree plans often provide supplemental coverage that helps pay for costs that Medicare does not cover, such as copayments, coinsurance, and deductibles. However, retiree plans are not considered creditable coverage for Part B purposes, so you should still enroll in Part B when you are first eligible to avoid the late enrollment penalty.

If you have Medicaid, Medicare is the primary payer and Medicaid is the secondary payer. Medicaid may help pay for your Part B premium, as well as for costs that Medicare does not cover, such as long-term care. If you have a Medigap policy, it works alongside Original Medicare to help pay for out-of-pocket costs. If you have a Medicare Advantage Plan, you do not need a Medigap policy, and in most cases, you cannot use a Medigap policy with a Medicare Advantage Plan. Understanding how your various coverages interact can help you make informed decisions about your healthcare and avoid unnecessary costs.

How to Enroll in Medicare Part B

Enrolling in Medicare Part B is a straightforward process, but it is important to follow the correct steps to ensure your coverage begins on time. If you are already receiving Social Security or Railroad Retirement benefits, you will be automatically enrolled in Part B and do not need to take any action. You will receive your Medicare card in the mail about three months before your 65th birthday. If you do not want Part B, you must follow the instructions that come with your card to decline coverage.

If you are not receiving Social Security benefits, you can enroll in Part B online through the Social Security Administration website at ssa.gov, by calling Social Security at 1-800-772-1213, or by visiting your local Social Security office. You will need to provide your Social Security number, date of birth, and information about any other health insurance you have. If you are enrolling during a Special Enrollment Period, you may also need to provide proof of your creditable coverage, such as a letter from your employer or insurance company.

Your Part B coverage will begin on the first day of the month after you enroll, or on the first day of your birth month if you enroll during your Initial Enrollment Period. For example, if you turn 65 in June and enroll in April, your coverage will begin on June 1. If you enroll in July (after your birth month), your coverage will begin on August 1. It is important to enroll as early as possible during your IEP to avoid any gaps in coverage and to avoid the late enrollment penalty.

Medicare Part B and Taxes

Medicare Part B premiums can have implications for your taxes, particularly if you are self-employed or itemize your deductions. If you are self-employed and pay for your own Medicare Part B coverage, you may be able to deduct the premiums as an above-the-line deduction on your federal income tax return. This deduction is available regardless of whether you itemize your deductions, and it can reduce your adjusted gross income (AGI), which may make you eligible for other tax benefits.

If you itemize your deductions on Schedule A, you may be able to deduct your Medicare Part B premiums as a medical expense, but only to the extent that your total medical expenses exceed 7.5% of your adjusted gross income. For example, if your AGI is $50,000 and your total medical expenses (including Part B premiums) are $5,000, you can only deduct the amount that exceeds $3,750 (7.5% of $5,000), which is $1,250. This threshold applies to all medical expenses, not just Medicare premiums.

Additionally, if you have a Health Savings Account (HSA), you cannot contribute to an HSA once you enroll in Medicare. However, you can use your existing HSA funds to pay for Medicare Part B premiums tax-free. This is a valuable benefit that can help you manage your healthcare costs in retirement. If you are still working and have an HSA, you may want to delay enrolling in Medicare to continue contributing to your HSA, but be sure to weigh the tax benefits of HSA contributions against the cost of delaying Medicare coverage.

Common Medicare Part B Mistakes to Avoid

One of the most common and costly mistakes is failing to enroll in Part B during your Initial Enrollment Period when you do not have creditable coverage through a current employer. As discussed earlier, the late enrollment penalty is permanent and can significantly increase your lifetime Medicare costs. If you are unsure whether your employer coverage is creditable, contact your employer's benefits administrator or the Social Security Administration before making a decision.

Another common mistake is assuming that Part B covers everything. While Part B provides comprehensive coverage for outpatient services, it does not cover everything. Part B does not cover most dental care, vision care, hearing aids, long-term care, or cosmetic surgery. It also does not cover prescription drugs you take at home — those are covered under Part D. Understanding what Part B does and does not cover can help you plan for your healthcare needs and avoid unexpected out-of-pocket costs.

A third mistake is not reviewing your Part B coverage during the Medicare Open Enrollment Period, which runs from October 15 to December 7 each year. During this period, you can switch from Original Medicare to a Medicare Advantage Plan, switch from one Medicare Advantage Plan to another, or add, drop, or change your Part D prescription drug coverage. Failing to review your coverage annually can result in paying for coverage you do not need or missing out on better options that could save you money.

Medicare Part B and Medicare Advantage

When you enroll in Medicare, you have a choice between Original Medicare (Part A and Part B) and Medicare Advantage (Part C). Medicare Advantage Plans are offered by private insurance companies approved by Medicare, and they provide all of your Part A and Part B coverage, plus additional benefits such as prescription drug coverage, dental, vision, and hearing benefits. Many Medicare Advantage Plans have lower out-of-pocket costs than Original Medicare, but they typically require you to use a network of providers and may require referrals to see specialists.

If you choose Original Medicare, you can see any doctor or specialist who accepts Medicare, and you do not need referrals. However, you may want to purchase a Medigap policy to help cover the out-of-pocket costs that Original Medicare does not pay. If you choose a Medicare Advantage Plan, you cannot use a Medigap policy, and in most cases, you cannot purchase one if you switch to a Medicare Advantage Plan. The choice between Original Medicare and Medicare Advantage depends on your individual healthcare needs, budget, and preferences.

It is important to note that regardless of whether you choose Original Medicare or Medicare Advantage, you must still pay your Part B premium. Medicare Advantage Plans may offer a rebate on your Part B premium, but you are still responsible for paying the premium to the Social Security Administration. Additionally, if you enroll in a Medicare Advantage Plan and later decide to switch back to Original Medicare, you may have difficulty purchasing a Medigap policy, as medical underwriting may apply outside of your initial enrollment period.