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What is Medicare Part B?

Understand what Medicare Part B covers, what it costs and when to enroll.

Page last updated on: 7/13/26

What is Medicare Part B?

Medicare Part B is administered by the federal government, and the enrollment process is generally similar to Part A. However, whether to enroll in Part B when first eligible may depend on individual circumstances, such as having health coverage through an employer or another source.

What does Part B cover?

Medicare Part B helps pay for medically necessary services and preventive care, including:

  • Doctor visits
  • Outpatient care
  • Laboratory tests
  • Surgeries and medical procedures
  • Preventive services and screenings

Who is eligible?

You can enroll in a Medicare Part B plan at any time during the enrollment period that applies to your situation. Even if you don’t think you need Part B coverage right away, it’s important to carefully evaluate your options. Delaying enrollment may result in a late enrollment penalty, which can increase your monthly premiums and overall costs for as long as you have Part B coverage.

When can you enroll?

Enrolling in Medicare Part B is similar to Part A, but the right timing depends on your health coverage and personal situation.

If you already have private or employer-sponsored insurance, you may not need Part B right away. Check with your insurance provider to understand your options.

In some cases, such as when you or your spouse is still working and covered by an employer health plan, you may be able to delay Part B enrollment without facing late enrollment penalties.

For those with TRICARE

  • If you have Part A and TRICARE (insurance for active-duty military or retirees and their families), you must have Part B to keep your TRICARE coverage unless the service member who carries the coverage is on active duty.

If you're nearing 65 and you're not receiving Social Security or Railroad Retirement Board (RRB) benefits, you'll want to apply for Part B (if you need it) as soon as you can. Similar to Part A, you can apply by:

If you already receive Social Security or RRB benefits, you don't need to do anything. You'll receive a Medicare red-white-and-blue card about three months before your 65th birthday. If disabled, you'll receive your card during your 25th month of disability. If you decide you don’t want Part B, simply follow the instructions on the card and return it.

Medicare Part B deductible: In 2026, the annual Part B deductible is $283, which helps cover 80% of services, including lab tests, surgeries and doctor visits.

Medicare Part B premium: In 2026, the standard Part B monthly premium is $202.90, but it increases for individuals and married couples with incomes above certain thresholds.

If you don't sign up for Part B when you are first eligible for Medicare, you may be penalized depending on whether your coverage is creditable or not. 

Creditable coverage is coverage provided by an employer group or union that offers benefits comparable to Original Medicare.

In some situations, you may be eligible for Medicare before you turn 65, or you may need some parts of Medicare to keep your current health plan or add other coverage.

For those with a particular disease

  • If you have amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease, you automatically get Part A and Part B the month your disability benefits begin.
  • If you have End-Stage Renal Disease (ESRD) you can apply for Part A and Part B.

A + B = What's next? 

Let's take the next step and explore Medicare Part C, the coverage option designed to simplify your Medicare experience.

Discover Medicare Advantage

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