How to Use the Part D Penalty Calculator
Not sure how the penalty works? It’s simple:
- Step 1: Enter how many full months you went without having Part D or other creditable drug coverage.
- Step 2: We’ll calculate your estimated penalty amount based on the national base premium for 2025.
- Step 3: Review your estimated penalty and see how it could affect your future Medicare costs.
2025 Part D Late Enrollment Penalty Calculator
Enter the number of months you were eligible to enroll but didn't:
Quick answers about the part d penalty
The penalty is 1% of the national base premium times the number of full months you didn’t have Part D or creditable coverage. It’s added to your monthly premium.
The Part D penalty lasts for as long as you have Medicare drug coverage — it’s a lifetime penalty
In very rare cases, you can appeal the penalty if you had creditable coverage and can prove it. Otherwise, it's permanent..

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Part D Late Enrollment Penalty Overview
The Part D late enrollment penalty is a permanent addition to your Medicare drug coverage (Part D) premium if you experience a period of 63 or more consecutive days without Medicare drug coverage or other creditable prescription drug coverage after your Initial Enrollment Period. The penalty is calculated by multiplying 1% by the "national base beneficiary premium" and the number of full, uncovered months you were eligible for Medicare drug coverage but did not enroll.
Late enrollment penalty calculator 2025:
In 2025, the Medicare Part D late enrollment penalty is calculated as 1% of the "national base beneficiary premium" which is currently set at $36.78, meaning for each uncovered month, you would pay a penalty of approximately $0.37 added to your monthly premium.
Understanding Medicare Part D Late Enrollment Penalty Calculator.
- The Part D late enrollment penalty is a permanent addition to your Medicare drug coverage (Part D) premium if you experience a period of 63 or more consecutive days without Medicare drug coverage after your Initial Enrollment Period.
- The penalty is calculated as 1% of the "national base beneficiary premium" multiplied by the number of full, uncovered months you were eligible for Medicare drug coverage but did not enroll.
- In 2025, the penalty amounts to 1% of the "national base beneficiary premium" ($36.78), leading to a penalty of approximately $0.37 per uncovered month added to your monthly premium.
When is a Part D enrollment considered "late?"
Typically, enrollment is deemed late if you did not enroll within three months of initially receiving Original Medicare (Parts A and B).
Enrollment Exemptions
- You will be exempt from the Part D late enrollment penalty if you:
- Qualify for Extra Help, also referred to as the Part D Low-Income Subsidy (LIS)
Have "creditable coverage" (coverage deemed comparable to Medicare drug coverage) from your or your spouse's employment, retiree benefits, or the Veterans Administration (VA)

Example of a 14 month late enrollment for Part D.
Calculation of the Part D Late Enrollment Penalty
- The penalty calculation amount is rounded to the nearest $0.10 and is added to your monthly premium for your Medicare drug coverage.
- The penalty may increase annually due to the escalation in the "national base beneficiary premium."
- For example, delaying enrollment by 14 months may result in a 14% late enrollment penalty in addition to your monthly plan premium.
Avoid Part D Late Enrollment Penalty
- You may avoid paying a Part D penalty if:
- You have creditable drug coverage (similar in value to Part D) or qualify for Extra Help.
- You may incur an extra 1% penalty for each month (12% annually) if you:
- Don't join a Medicare drug plan when you first become eligible.
- Go 63 days or more without creditable drug coverage.
- Your premium amount may also vary based on your income.
The best way to avoid the Part D penalty is to sign up for a Medicare Drug plan during your IEP. For information about plans and signing up check out our online Medicare plan finder.
Penalty Duration and Exceptions
- The Part D late enrollment penalty remains in effect as long as you maintain Medicare drug coverage, regardless of switching plans.
- Individuals receiving Extra Help are exempt from paying the penalty.
Disputing the Part D Late Enrollment Penalty
- If you believe the penalty is inaccurate, you can request a reconsideration within 60 days of receiving the notice.
- Provide supporting evidence and submit the form to Medicare's contractor, who aims to make a decision within 90 days.
- Note that the penalty must be paid even if you disagree with it, with non-payment potentially resulting in disenrollment from your Medicare drug plan.
Outcome of the Reconsideration Decision
- If the contractor deems the penalty incorrect, adjustments will be made, and you may receive a refund.
- If the penalty is valid, you'll be required to pay as determined.
Medicare Part D Penalty FAQ
The penalty is 1% of the national base premium times the number of full months you didn’t have Part D or creditable coverage. It’s added to your monthly premium.
The Part D penalty lasts for as long as you have Medicare drug coverage — it’s a lifetime penalty
In very rare cases, you can appeal the penalty if you had creditable coverage and can prove it. Otherwise, it's permanent..