By: Eligibility Team | March 19, 2019

Medicare Part B is one of the two parts of Original Medicare, the federal government-managed health care program for people over age 65 and those with certain disabilities. Part B, often referred to as “medical insurance,” covers services and supplies that are considered medically necessary to treat a condition or disease. This coverage contrasts with Part A “hospital insurance,” which covers hospital services, home health care, skilled nursing facilities, and certain other services.

You’ll need to enroll in Medicare Part B coverage when you are initially eligible—the three months before and the three months after your 65th birthday—or you’ll have to pay a penalty to enroll later. There are exceptions for people who are still working; they can wait to enroll once their employer-based coverage ends. People who have certain disabilities will be automatically enrolled after receiving 24 months of Social Security benefits.

What Medicare Part B covers

Part B covers two general categories of care: medically necessary services and preventive care. Medically necessary services generally require you to pay a copay or coinsurance, but you get preventive services at no cost.

What Part B includes:

part b coverage

The government defines medically necessary services as “services or supplies that are needed to diagnose or treat your medical condition and that meet accepted standards of medical practice.” Essentially, they’re the things that help you recover from being sick or injured.

These services include a variety of benefits, from wheelchairs to help you after knee surgery to a doctor’s office visit for the flu. Common medically necessary services include the following:

  • Ambulance services
  • Doctor’s office visits
  • Durable medical equipment
  • Laboratory tests
  • Mental health and chemical dependency care
  • Outpatient (same-day) hospital stays
  • Home health care not associated with a hospital stay

Some services require prior authorization to be covered. Check with your health care provider to find out if prior authorization is required.

Preventive care includes services that are designed to help you be well or keep you from getting sick. Medicare defines preventive services as “health care to prevent illness (like the flu) or detect it at an early stage, when treatment is most likely to work best.” Here are some common preventive services covered by Part B Medicare:

  • Annual wellness visits
  • Cancer screening tests
  • Diabetes screenings
  • Flu shots
  • HIV and STD screening and counseling
  • Nutrition therapy
  • Tobacco cessation counseling

How much Medicare Part B costs

Medicare Part B has three cost types: premiums, deductibles, and coinsurance. These are the costs for 2017:

  • The standard Part B premium is $134 per month (or more, depending on income).
  • The Part B deductible is $183 per year.
  • The Part B coinsurance is 20 percent (of the amount Medicare approves).

These are the costs for new plans purchased in 2017. If you have been receiving Medicare before 2017 and pay your premiums through Social Security benefits, you may pay less ($109 on average). See our guide to Medicare Part B premiums.

Medicare Part B premium

Unlike Part A coverage, which has no premium, Part B requires you to pay a monthly premium. This premium is deducted from your Social Security benefits, or, if you don’t receive Social Security, you will get a bill.

The federal government sets the standard Part B premium each year, but how much you actually pay depends on your income. Many Part B enrollees don’t pay the standard premium amount; they pay an Income Related Monthly Adjusted Amount (IRMAA) instead. If you have Medicaid in addition to Medicare, your state Medicaid program will pay your Medicare Part B premium.

Medicare Part B deductible

A deductible is the amount you must pay for medically necessary services before Medicare begins paying. Each year, you must satisfy the Part B deductible. Once you’ve met the deductible, you’ll begin paying the Part B coinsurance.

Part B coinsurance

Coinsurance splits the cost of covered services between you and Medicare. For Part B coverage, you’ll pay 20 percent of the amount that Medicare approves once you meet the deductible. For example, if Medicare approves $50 per month for a wheelchair rental, you’ll pay $10 (20 percent) and Medicare will pay $40 (80 percent).

How to get Medicare Part B

Your first—and most important—chance to enroll in Medicare Part B is just before you turn 65. You have the three months before and after your birthday month to enroll.

Initial Enrollment

If you want Part B coverage, it’s important that you enroll during this initial period because if you don’t, you’ll have to wait until the next enrollment period, which is January through March. If you enroll at that time, your Part B coverage won’t begin until July 1.

If you miss both of those initial Part B enrollment periods and wait more than a year, you may have to pay a penalty for signing up later. This penalty is permanently applied to your Part B premium. According to Herald & Review, penalties raised Part B premiums by 29 percent on average.

How to Enroll

You have a few options to sign up for Medicare Part B. Some people are automatically enrolled, like those already getting Social Security benefits, but many have to sign up themselves.

You’ll be enrolled automatically and get your Medicare card three months before your 65th birthday if you meet one of these requirements:

  • You currently get Social Security benefits.
  • You are disabled and get disability benefits.
  • You have Amyotrophic Lateral Sclerosis (ALS).

You need to sign up for Part B coverage yourself if you fall under these conditions:

  • You don’t receive Social Security benefits.
  • You have End-Stage Renal Disease (ESRD).
  • You live in Puerto Rico.

If you need to sign up for Part B coverage, you can do so by one of these methods:

  • Online. Apply online on the Social Security Administration’s website.
  • In person. Apply in person at a Social Security office.
  • By phone. Call the Social Security Administration at 1-800-772-1213 (TTY: 1-800-325-0778).

More questions?

If you’re wondering about alternatives to Original Medicare Part B coverage, we can help. You may be able to sign up for Medicare Advantage, a Medicare Supplement plan, or a Medicare Part D Prescription Drug Plan.

If you have more questions about Medicare Part B, such as Can I sign up for Medicare Part B if I have coverage through Obamacare? read answers to some frequently asked questions.