Enrolling in Medicare late an result in late enrollment penalties, meaing that you will pay a higher premium for as long as you have Medicare coverage. The amount of penalty will vary depending on the part of Medicare you are enrolling in late. In most cases, you can avoid these penalties by enrolling during your Initial Enrollment Period or during a Special Enrollment Period if you qualify.

Medicare Part A Penalty #

This penalty only applies if you are required to pay a premium for Part A. If you are required to pay a premium for Part A, and you sign up late, the penalty is 10% of your monthly premium. This penalty is applied for twice the number ofyears you delayed enrollment.

For example, in 2025 the Part A premium cost for those that do not qualify for premium-free coverage, starts at $285 per month. If you delayed signing up for Part A for two years, you would pay the normal $285 per month, plus an additional $28.50 per month for the following 4 years. After 4 years, the penalty would be removed.

Medicare Part B Penalty #

Part B penalty applied to anyone who delays enrolling in Part B without other creditable coverage. The penalty causes your monthly premiums to be increased by 10% per year you went without coverage. This penalty is applied for as long as you have Part B.

For example, if you delayed enrollment for 2 years, you would pay an additional 20% per month every month for as long as you continue to have Part B coverage.

Medicare Part D Penalty #

Medicare Part D penalties are the most common. You are given a penalty if, after 63 days past when you are first eligible for Medicare, you did not have creditable coverage. The amount of penalty is calculated as 1% of the ‘national base beneficiary premium’ (this amount changes every year, but it is $36.78 in 2025) multiplied by the number of months you went without coverage.

For example, if you went 14 months without Part D coverage, you would pay $5.15 (14% of $36.78) extra every single month. Short of enrolling in the Extra Help program, or receiving Medicaid benefits, you will pay this penalty for the entire time that you are enrolled in a Part D plan.