What is Medicare Part B?

Medicare Part B (which is medical insurance) is part of Original Medicare and covers medical services and supplies that are medically necessary for treating your health condition. This may include outpatient care, preventive services, ambulance services, and durable medical equipment (DME). It will also cover part-time or intermittent home health and rehabilitative services, like physical therapy, if they are prescribed by a doctor for treating your condition.

Some preventive services are also covered by Medicare Part B including a one-time “Welcome to Medicare” preventive visit, flu and hepatitis B shots, cardiovascular screenings, cancer screenings, diabetes screenings, and more. For a full list of the preventive services covered under Medicare Part B, please 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 with Original Medicare such as routine dental and/or vision, hearing, a health club membership, and even prescription drug coverage.

Eligibility for Medicare Part B

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

You can 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

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 31, with coverage starting on July 1. You may have to pay a late enrollment penalty for not signing up when you were first eligible.

If you’re not automatically enrolled, 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 7 AM to 7 PM, Mon through Fri.

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

Delaying Medicare Part B enrollment

If you are still employed, 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 group coverage, you may sign up later during a Special Enrollment Period (SEP) 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 your current employment. After your employer’s health coverage ends or your employment ends (whichever comes first), you have an eight-month SEP to sign up for Part B without incurring a late enrollment 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 SEP. 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 following when your current employment or group plan ends (whichever comes first). This is regardless of whether you get COBRA.

Medicare Part B Premiums/Deductibles

Medicare Part B covers physician services, outpatient hospital services, certain home health services, durable medical equipment, and certain other medical and health services not covered by Medicare Part A. 

Each year the Medicare premiums, deductibles, and coinsurance rates are adjusted according to the Social Security Act. For 2021, the Medicare Part B monthly premiums and the annual deductible are higher than the 2020 amounts. The standard monthly premium for Medicare Part B enrollees will be $148.50 for 2021, an increase of $3.90 from $144.60 in 2020. The annual deductible for all Medicare Part B beneficiaries is $203 in 2021, an increase of $5 from the annual deductible of $198 in 2020.

The Part B premiums and deductibles reflect the provisions of the Continuing Appropriations Act, 2021, and Other Extensions Act (H.R. 8337).

CMS is committed to empowering beneficiaries with the information they need to make informed decisions about their Medicare coverage options, including providing new tools to help them make those decisions through the medicare initiative. In addition to the recently released premiums and cost-sharing information for 2021 Medicare Advantage and Part D plans, we are releasing the premiums and cost-sharing information for Fee-for-Service Medicare, so beneficiaries understand their options for receiving Medicare benefits. As previously announced, average 2021 premiums for Medicare Advantage plans are expected to decline 34.2 percent from 2017 while plan choices, benefits, and enrollment continue to increase. The Medicare Advantage average monthly premium will be the lowest in fourteen years (since 2007). Premiums and deductibles for Medicare Advantage and Medicare Part D Prescription Drug plans are already finalized and are unaffected by this announcement.

Medicare Part B Income-Related Monthly Adjustment Amounts

Since 2007, a beneficiary’s Part B monthly premium is based on his or her income. These income-related monthly adjustment amounts affect roughly 7 percent of people with Medicare Part B. The 2021 Part B total premiums for high-income beneficiaries are shown in the following table:

Premiums for high-income beneficiaries who are married and lived with their spouse at any time during the taxable year, but file a separate return, are as follows: