Medicare Part B is a health insurance program that covers a broad range of medically necessary services that aren’t covered by Medicare Part A. These services include ambulance services, surgery, dialysis, mental health care, physical therapy, and more. In addition, Part B covers diagnostic tests and preventive services, such as HIV screenings and colorectal cancer screenings. The Part B monthly premium varies depending on a person’s income. People with a higher income pay a higher premium.

The Part B monthly premium is set each year by the Centers for Medicare & Medicaid Services (CMS) and can vary depending on the person’s income. People with a higher income pay a higher premium.

People who don’t want to have Part B coverage can choose to not enroll in it, but they will have to pay a Part B late enrollment penalty if they decide to sign up later. The late enrollment penalty is an added fee that’s tacked on to your monthly premium for as long as you have Part B coverage. It’s calculated based on how long you waited to sign up for Part B after you became eligible.

Medicare Part B premiums for most enrollees are deducted from their Social Security checks. But there’s a “hold harmless” rule that prevents net Social Security checks from declining from one year to the next unless the person has an income of $91,000 or more (that income limit is for 2022 coverage, and is based on 2020 tax returns).