What Is Medicare Part B?

Medicare Part B (medical insurance) is part of Original Medicare and covers services and supplies that are medically necessary to treat your health condition. This can include outpatient care, preventive services, ambulance services, and durable medical equipment. It also covers part-time or intermittent home health and rehabilitative services, such as physical therapy, if they are ordered by a doctor to treat your condition.

Some of the preventive services Medicare Part B covers include a one-time "Welcome to Medicare" physical exam, flu and hepatitis B shots, cardiovascular screenings, cancer screenings, diabetes screenings, and more. For a full list of preventive services covered under Medicare Part B, refer to the Medicare handbook, "Medicare and You."

If you are in a Medicare Advantage plan, you would get both your Medicare Part A and Part B coverage through a private health insurance company contracted with Medicare. By law, Medicare Advantage plans must offer at least the same level of coverage as Original Medicare, and some plans include additional coverage not included in Original Medicare such as routine dental and/or vision, hearing, and even prescription drug coverage.

Eligibility for Medicare Part B

Anyone who is eligible for premium-free Medicare Part A is eligible for Medicare Part B by enrolling and paying a monthly premium. If you are not eligible for premium-free Medicare Part A, you can qualify for Medicare Part B by meeting the following requirements:

  • You must be 65 years or older.
  • You must be a U.S. citizen, or a permanent resident lawfully residing in the U.S for at least five continuous years.


You may also qualify for automatic Medicare Part B enrollment through disability. If you are under 65 and receiving Social Security or Railroad Retirement Board (RRB) disability benefits, you will automatically be enrolled in Medicare Part A and Part B after 24 months of disability benefits. You may also be eligible for Medicare Part B enrollment before 65 if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (also known as ALS, or Lou Gehrig's disease).

When to enroll in Medicare Part B

Unless you are receiving retirement benefits before age 65 or qualify for Medicare through disability, you will need to sign up for Medicare Part B during your Initial Enrollment Period (IEP). This is the seven-month enrollment period that begins three months before you turn 65, includes the month you turn 65, and ends three months later. Your Medicare coverage start date will depend on which month you signed up during initial enrollment. If you have health coverage through an employer health plan, you may choose to delay enrollment, since Medicare Part B comes with a monthly premium.

If you do not enroll during your initial enrollment period and do not qualify for a special enrollment period, you can also sign up during the annual General Enrollment Period, which runs from January 1 to March 30. You may have to pay a late enrollment penalty for not signing up when you were first eligible.

You can apply for Medicare through Social Security, either in person at a local Social Security office, through the Social Security website, or by calling 1-800-772-1213 (TTY users 1-800-325-0778) from 7AM to 7PM, Monday through Friday.

Keep in mind that once you are both 65 years or older and have Medicare Part B, your six-month Medigap Open Enrollment Period begins. This is the best time to purchase a Medicare Supplement plan because during open enrollment, you have a "guaranteed-issue right" to buy any Medigap plan without medical underwriting or paying a higher premium due to a pre-existing condition. Once you are enrolled in Medicare Part B, be careful not to miss this one-time initial guaranteed-issue enrollment period for Medigap.

Delaying Medicare Part B enrollment

Some people may get Medicare Part A "premium-free," but most people have to pay a monthly premium for Medicare Part B. Because Medicare Part B comes with a monthly premium, some people may choose not to sign up during their initial enrollment period if they are currently covered under an employer group plan (either their own or through their spouse's employer).

If you are still working, you should check with your health benefits administrator to see how your insurance would work with Medicare. If you delay enrollment in Medicare Part B because you already have current employer health coverage, you can sign up later during a Special Enrollment Period without paying a late penalty. You can enroll in Medicare Part B at any time that you are still covered by a group plan based on current employment. After your employer health coverage ends or your employment ends (whichever comes first), you have an eight-month special enrollment period to sign up for Part B without a late penalty.

Keep in mind that retiree coverage and COBRA are not considered health coverage based on current employment and would not qualify you for a special enrollment period. If you have COBRA after your employer coverage ends, you should not wait until your COBRA coverage ends to sign up for Medicare Part B. Your eight-month Part B special enrollment period begins immediately after your current employment or group plan ends (whichever comes first). This is regardless of whether you get COBRA.

Medicare Part B premiums

Medicare Part B premiums may change from year to year, and the amount can vary depending on your situation. For many people, the premium is automatically deducted from their Social Security benefits.

If you were enrolled in Medicare Part B before 2016, your monthly premium is typically $104.90 in 2016. Your monthly premium is generally $121.80 in 2016 if any of the following applies to you:

  • You enrolled in Medicare Part B for the first time in 2016.
  • You get billed for your Part B premium (instead of having it automatically deducted from your Social Security benefits).
  • You don't receive Social Security benefits.
  • You quality for both Medicare and Medicaid benefits (you're dual-eligible).
  • Your income exceeds a certain amount. Your premium could be higher than the amount listed above, as there are different premiums for different income levels.


See below for more details about the Medicare Part B premium.

If you are receiving Social Security, Railroad Retirement Board, or federal retirement benefits, your Part B premium will be deducted directly from your monthly benefit. If not, you will be sent a bill every three months.

The chart below shows the Medicare Part B monthly premium amounts, based on income. These amounts may change each year. A late enrollment penalty may be applicable if you did not sign up for Medicare Part B when you were first eligible. Your monthly premium may be 10% higher for each 12-month period that you were eligible, but didn't enroll in Part B.

Medicare Part B Monthly Premium in 2016
Source: "Part B Costs," Medicare.gov
You payIf your yearly income is
If you filed an individual tax returnIf you filed a joint tax return
$121.80 ($104.90 if you enrolled in Part B before 2016)$85,000 or less$170,000 or less
$170.50$85,001 - $107,000$170,001 - $214,000
$243.60$107,001 - $160,000$214,001 - $320,000
$316.70$160,001 - $214,000$320,001 - $428,000
$389.80Above $214,000Above $428,000
You pay If you are married but you file a separate tax return from your spouse and your yearly income is
$121.80 ($104.90 if you enrolled in Part B before 2016) $85,000 or less
$316.70 $85,001-$129,000
$389.80 Above $129,000

Medicare Part B deductible and coinsurance amounts

The annual deductible for Medicare Part B is $166 in 2016. You will also be responsible for a 20% coinsurance. If your doctor or health care provider accepts assignment for a covered service, you would pay the Part B deductible along with 20% of the Medicare-approved amount for services rendered. Accepting assignment means that your doctor will not charge you more than the Medicare-approved amount for the covered service. You would still be responsible for cost-sharing.

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