The Part B late enrollment penalty raises your monthly Part B premium by 10 percent for every full twelve-month period you could have had Part B but did not sign up, and you pay it for as long as you have Medicare. Two full years late means a 20 percent higher premium every month for life. The penalty does not apply if you delayed because you had active employer coverage from a job with 20 or more employees.
An example
The 2026 premium is $202.90. Someone who waited two full years pays 20 percent more, about $243.50 a month, and that markup follows the premium up every year afterward. Over twenty years of Medicare, that is roughly $10,000.
Who is exempt
If you or your spouse were actively working and covered by that employer's group plan, you can delay Part B and enroll later in a Special Enrollment Period with no penalty. The window is eight months from the month the job or the coverage ends, whichever comes first.
Retiree coverage, COBRA and individual plans do not count. People in those situations who delay Part B get the penalty.
Enrolling late without an exemption
If you miss your Initial Enrollment Period and have no Special Enrollment Period, you can only sign up during the General Enrollment Period, January 1 to March 31 each year. Coverage starts the first of the month after you enroll. Between your missed window and that date you have no Part B at all, which means no coverage for doctor visits.
Part A is different
Part A is free for most people, so there is no reason to delay it, and there is no penalty for the free version. Only the small number of people who pay a Part A premium face a Part A penalty.
Fixing a mistake
If you delayed because a government representative gave you wrong information, you can apply for equitable relief through Social Security and ask to have the penalty removed. Written proof of what you were told helps.
The date finder on the home page shows your window. If you are working past 65 or unsure whether your coverage counts, request a plan check and I check it before you decide.