You will have to pay a late enrollment penalty if you do not enroll in Medicare Part B when you become eligible. Online resources can help you calculate how much this fee will be.
If you do not sign up for Medicare Part B during your initial enrollment period or do not have other coverage that is equivalent to Medicare from an employer, you will have to pay a late penalty.
The Part B late enrollment penalty is not a one-time fee. It is added to your monthly premium for the entire time you have Medicare.
The thought of having to pay a penalty can be stressful. You can find tools online to help you calculate what your fee may be.
Examples of online Part B penalty calculators include:
These calculators allow you to input the amount of time you have delayed enrolling in Medicare Part B. They then give you an estimate of how much your late fee will be.
You pay this penalty in addition to the monthly premium. In 2025, that premium is $185 or higher, depending on income.
The Part B late enrollment penalty is an extra 10% on top of the monthly premium for each 12-month period you delay enrollment.
Calculation example
If you delayed Medicare enrollment for 7 years and did not have adequate health coverage that allows delay, your monthly premium would be 70% higher. This is calculated by multiplying the number of years delayed by 10% (7 x 10% = 70%).
The standard Part B premium is $185. To figure out the actual dollar amount of the fee, you would multiply the 70% penalty by $185, which amounts to $129.50 (0.7 x $185 = $129.50).
You would then add that fee amount to the monthly premium that you pay. So, if you pay the standard monthly premium, it would be $129.50 + $185 = $314.50.
This means your monthly premium with the penalty would be $314.50.
A note on Part B late enrollment penalty
Your Part B monthly premium is based on your income. In 2025, if you make over $106,000, you will pay a higher premium depending on how much your income is over that amount.
However, the Part B late enrollment penalty is calculated based on the standard premium of $185, and the fee is added to your actual monthly premium.
Example
If your income is between $106,000 and $133,000, your monthly premium would be $259. If you take the 7-year penalty calculation from above, your monthly premium with the penalty fee would be $388.50. This is the late penalty fee ($185 x 0.7 = $129.50) added to the monthly premium of $259 ($129.50 + $259 = $388.50).
The main way you can avoid a Part B late enrollment penalty is to enroll in Medicare as soon as you become eligible.
The initial enrollment period begins 3 months before your 65th birthday and runs for 3 months after your birth month. You can enroll in Medicare any time during this 7-month period.
Other health coverage
If you have other health coverage through your employer or your spouse’s employer when you become eligible for Medicare, you can qualify for a special enrollment period.
This allows you to delay enrollment in Medicare by 8 months after your initial enrollment period ends.
Special enrollment period
If you miss your initial enrollment period, you may qualify for a special enrollment period in certain situations.
Examples of circumstances that qualify you for a special enrollment period are:
- You missed the chance to sign up due to a natural disaster.
- You missed the chance to sign up due to misleading or inadequate information from your employer or health plan.
- You have or had health insurance through your job or your spouse’s job.
- You missed the chance to sign up due to other exceptional circumstances. This requires you to contact the Social Security Administration (SSA) to request a special enrollment.
Part B penalty waiver
You have the right to appeal your late enrollment penalty determination with the SSA.
You can do this by following the directions on the letter from the SSA regarding your penalty. If you do not have this letter, you can file a Request for Reconsideration form.
You can appeal the penalty decision if you were continuously covered by employer health coverage or Part B. Another reason for appeal is if you feel your fee was calculated incorrectly.
How long does the Part B penalty last?
The Part B late enrollment penalty typically lasts for as long as you have Part B.
Is there a cap to the Part B penalty?
There is currently no cap for the Part B late enrollment penalty. You are responsible for paying the extra 10% fee along with your monthly premium for as long as you have Medicare Part B.
If you do not sign up for Medicare Part B when you become eligible for Medicare, you will be responsible for paying a late enrollment penalty. This is in addition to your monthly Part B premium and lasts for as long as you have Part B.
Online calculators can help you calculate how much this penalty will be.
In limited circumstances, you can appeal this fee with the SSA.