If a person does not enroll in Medicare Part B (out-patient care and doctor visits) when first eligible, and they do not have health coverage from an employer group health plan, they will incur a late-enrollment penalty if they later choose to enroll in Medicare Part B.

This is also true if someone has Medicare Part B, but then drops their Part B coverage, and then later decides to sign up again for coverage.

Remember, if a person does not enroll in Medicare Part A and/or Medicare Part B when they were first eligible, and they were not eligible for a Special Enrollment Period, they can only elect Medicare Part A or Medicare Part B during the General Enrollment Period that starts January 1st and continues through March 31 of each year.

The Medicare Part B late-enrollment penalty is 10% of the current Medicare Part B premium for every 12-month period that the person delayed enrolling in Medicare Part B after they were first eligible or dropped Part B and were without Medicare Part B coverage when they were eligible.

For example, the 2024 standard Medicare Part B premium is $174.70 (for most people), so if a person delays enrolling in Medicare Part B (and has no employer coverage) for 12 months, they will have a 10% penalty of $17.47 in 2024 -- 10% for each year you could have signed up for Part B, but didn't.

You can read more about the most recent changes in Medicare Part B premiums in our Medicare articles.

The Medicare Part B penalty is permanent and will be paid for as long as the person has Medicare Part B coverage.

Please note that a person may be excluded from paying a Medicare Part B late-enrollment penalty if they meet certain conditions allowing them to sign up for Medicare Part B during a Special Enrollment Period (for example, as noted by Medicare, a person will have an 8-month Special Enrollment Period to enroll in Medicare Part A and/or Medicare Part B starting the month after the employment ends or the group health plan insurance based on current employment ends, whichever happens first).

Examples of the Medicare Part B late-enrollment penalty provided by Medicare

Older Example: "Your Initial Enrollment Period ended September 30, 2009. You waited to sign up for Medicare Part B until the General Enrollment Period in March 2012. Your Part B premium penalty is 20%. (While you waited a total of 30 months to sign up, this included only 2 full 12-month periods.) You’ll have to pay this 20% penalty for as long as you have Medicare Part B coverage."

(Previously found at: https://www.medicare.gov/ your-medicare-costs/ part-b-costs/penalty/ part-b-late-enrollment-penalty.html)

2023 Example: "If you waited 2 full years (24 months) to sign up for Part B and didn’t qualify for a Special Enrollment Period, you’ll have to pay a 20% late enrollment penalty (10% for each full 12-month period that you could have signed up), plus the standard Part B monthly premium ($164.90 in 2023) ($174.70 in 2024).

 $164.90 (2023 Part B standard premium) ($174.70 in 2024)
+ $32.98 (20% [of $164.90] late enrollment penalty) ($34.94 in 2024)"

(see:  https://www.medicare.gov/ basics/costs/ medicare-costs/ avoid-penalties)

The Medicare Part B Initial Enrollment Period

A person can enroll in Medicare Part B during their 7-month Initial Enrollment Period when they first become eligible for Medicare (3 months before the Medicare eligibility month, plus the month a person turns 65, and including the 3 months after the month a person turns 65).  During the 7-month Initial Enrollment Period a person can also enroll in Medicare Part A, if they were not already automatically enrolled.

You can also learn more about Medicare Part B coverage in our Frequently Asked Questions:
q1medicare.com/faq/category/Medicare-Part-B/138