Medicare Part B – enrollee benefits and coverage costs

What is Medicare Part B?

Medicare Part B is designed to cover outpatient, physician, and preventive services that aren’t covered by Medicare Part A. Medicare Part B has a monthly premium, so people who continue to work after becoming eligible for Medicare often choose to delay their enrollment in Medicare Part B until after their job-sponsored insurance ends.

What does Medicare Part B cover?

Medicare Part B covers a broad range of medically necessary and preventive services that aren’t picked up by inpatient coverage – even though they might be received while a person is hospitalized. This includes physician visits, ambulance services, certain surgical procedures, dialysis, mental health care, physical therapy, transplants, chemotherapy and radiation, urgent care, and more.

In addition, Medicare Part B covers diagnostic tests (such as MRIs, CT scans, EKGs, and x-rays) and a host of preventive medical services, such as pap tests, HIV screening, glaucoma tests, hearing tests, diabetes screening, colorectal cancer screenings, and certain vaccines (other vaccines are covered under Medicare Part D instead). Medicare Part B also pays the costs of durable medical equipment such as wheelchairs, hospital beds, and oxygen equipment, and for drugs that are taken by infusion (most drugs are covered under Medicare Part D, but drugs administered via infusion are covered under Part B instead).

See if your test, item, or service is covered by Medicare.

What is the Medicare Part B premium for 2025?

For 2025, the Medicare Part B premium is $185/month for most enrollees.¹ (See below for an overview of how Medicare Part B premiums have changed over the years.)

Medicare Part B premiums can be covered by Medicaid if the beneficiary is eligible for both programs. And high-income enrollees pay more than the standard premiums for Medicare Part B.

Can I get Medicare Part B for free?

Some enrollees can get Medicare Part B for free. There are essentially three ways this is possible, and although they aren’t applicable to most Medicare beneficiaries, it’s useful to know what options are available for covering the cost of the premiums. Here are the scenarios:

• Your income and assets are low enough to qualify for full Medicaid or a Medicare Savings Program that covers the cost of Medicare Part B. Medicare Savings Programs are run by each state’s Medicaid office, and eligibility varies from one state to another.
• You or your spouse are continuing to work and the employer offers a QSEHRA or an ICHRA that reimburses your Medicare Part B premiums.
• You enroll in a Medicare Advantage plan that has a “giveback” rebate that covers the entire Medicare Part B premium. Giveback rebates are not the norm, but do tend to be available in most areas (for 2024, nearly one out of five Medicare Advantage plans included at least some amount of giveback rebates). However, the rebate amount can vary from as little as 10 cents per month to as much as the full premium. So it’s important to understand that many enrollees who get a giveback rebate do still have to pay something for Part B.
  

What is the 2025 IRMAA Part B surcharge?

Medicare Part B enrollees with income above $106,000 (single) / $212,000 (married) pay higher premiums than the rest of the Medicare population in 2025. (This threshold was $85,000/$170,000 prior to 2020, but it was adjusted for inflation starting in 2020.) The 2025 Medicare Part B premiums for high-income beneficiaries range from $259/month to about $629/month.³

This income-related monthly adjustment amount (IRMAA) is based on your income tax return from two years ago. That’s the most recent tax return they have on file at the start of the plan year (when the 2025 plan year begins, the most recent tax returns on file are for 2023, so 2023 income is used to determine IRMAAs for 2025). But if a life-change event has reduced your income since then, there’s an appeals process available. You can use it to request that the income-related premium adjustment be changed or eliminated without having to wait for it to reflect on a future tax return.

What is the Medicare Part B deductible?

Enrollees who receive treatment during the year that’s covered by Medicare Part B must also pay a deductible, which increased to $257 for 2025¹ (up from $240 in 2024; see below for an overview of how the Medicare Part B deductible has changed over time). After the deductible, enrollees also pay 20% of the Medicare-approved amount for care that’s covered under Medicare Part B, although supplemental coverage from a Medigap plan, Medicaid, or an employer-sponsored plan can be used to cover some or all of the Medicare Part B out-of-pocket costs.

Learn how Medicare premiums, deductibles and coinsurance changed for 2024.

Does everyone have to pay the Medicare Part B deductible?

No, not everyone pays the Medicare Part B deductible. People who don’t receive services under Medicare Part B (or who only receive deductible-free preventive services, such as vaccines), do not have to pay the deductible. And although most Medicare beneficiaries do receive services that are covered under Medicare Part B, some of them do not have to pay the Part B deductible:

• Medigap plans C and F cover the deductible, so if you still have one of those plans, you’re not responsible for paying the Medicare Part B deductible. (This is why those plans are no longer available to people who become newly eligible for Medicare after the end of 2019, under the terms of the Medicare Access and CHIP Reauthorization Act. The idea is that there will be less unnecessary utilization of health care if all Original Medicare enrollees are subject to the Part B deductible, but critics argue that it could also hinder access to necessary care.)
• Enrollees who have Medicaid, employer-sponsored health coverage, or retiree health benefits from an employer generally don’t have to pay the full Medicare Part B deductible, as the other coverage picks up some or all of the cost (this varies depending on the plan).
• Some Medicare Advantage plans have no deductibles and low copays. Medicare Advantage enrollees pay the Medicare Part B premium plus the Medicare Advantage premium (the majority of Medicare Advantage plans have no premium other than the cost of Medicare Part B), and then the Medicare Advantage insurer wraps the Medicare Parts A and B (and in most cases, Medicare Part D) benefits into one plan for the enrollee, with cost-sharing that can differ greatly from the standard Original Medicare cost-sharing.
  

How do I enroll in Medicare Part B?

If you are already receiving Social Security or Railroad Retirement benefits, you will be notified three months prior to your 65th birthday that you are about to be enrolled in Medicare Part A, and that Medicare Part B is an option. You’ll receive the Medicare Part B card at the same time as the Medicare Part A card.

If you choose not to enroll in Medicare Part B, you must return the card (which means you’re rejecting Medicare Part B coverage; more on that below) or the premium will automatically start to be deducted from your Social Security checks. If you keep the card, Medicare Part B coverage kicks in the month you turn 65.

If you’re not already receiving Social Security or Railroad Retirement benefits, you’ll have an opportunity to enroll in Medicare B (along with Medicare Part A) during a seven-month window that includes the three months before the month you turn 65, the month you turn 65, and the following three months.  If you enroll in the three months prior to the month you turn 65, your coverage will be effective the month you turn 65.

It’s important to note that if you fail to enroll in Medicare Part B during your seven-month enrollment period, the program will offer you another opportunity to enroll each succeeding year (January 1 – March 31), with coverage effective the month after you enroll (the effective date used to be July 1, but this changed as of 2023, under the BENES Act). The catch? If and when you do eventually enroll in Medicare Part B, for each year that you were eligible for Part B but turned it down, your monthly premium will be increased by 10%, and the higher rate will be in place for as long as you have Medicare Part B.

So if you wait three full years to enroll after your initial enrollment period, you’ll pay premiums that are 30% higher than the normal price, for as long as you have Medicare Part B coverage (generally, for life). The penalty does not apply, however, if you delay your Part B enrollment because you have other coverage in place from a current employer or your spouse’s current employer.

Should I delay Part B enrollment?

If you have health insurance through your current employer, or through your spouse’s current employer, you may want to delay enrollment in Medicare Part B, if your employer has 20 or more employees. You’ll need to check with your employer or HR department to make sure that your employer-sponsored coverage will pick up where Medicare Part A leaves off, but assuming it does, you may want to delay enrolling in Medicare Part B, since it has a premium.

This article explains more about what you need to know before making the decision to delay Part B.

Can I reject Medicare Part B altogether?

Medicare Part B is optional. You can choose to skip it altogether and avoid the premiums. But that means you’re on the hook for the full cost of any services that would otherwise be covered under Medicare Part B. For healthy enrollees, that might amount to the occasional office visit and nothing more. But if you end up needing extensive outpatient care — such as kidney dialysis, chemotherapy, radiation, physical therapy, etc. — your bills could add up quickly.