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Medicare Part D Late Enrollment Penalty Calculator
Find out if you owe a Part D penalty and exactly how much it adds to your premium — every month, for life.
LEP Estimator — CMS 2026
Calculate Your Penalty
Your 7-month Initial Enrollment Period (IEP) runs from 3 months before to 3 months after this month. The penalty clock starts the month after your IEP ends.
A gap of more than 63 consecutive days without creditable coverage triggers the penalty for those uncovered months. Your plan must send you an annual creditable coverage notice.
If not yet enrolled, your penalty is calculated through today and continues growing each month.
This penalty is permanent. It stays with you for as long as you have Part D coverage — even if you switch plans. CMS recalculates the dollar amount each year when the national base premium changes.
Your Part D Penalty Estimate
Penalty Clock Started—
Uncovered Months—
Penalty Percentage—
2026 Base Premium$38.99
Monthly Penalty (Added to Your Premium)—
Extra Annual Cost—
Don't let the penalty grow any larger.
The sooner you enroll, the less you pay. A licensed specialist can get you covered at no cost to you.
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How the Penalty Works
Penalty Rate
1% / mo
Per full uncovered month
2026 Base Premium
$38.99
CMS national base (42 CFR 423.286)
Grace Period
63 Days
Consecutive days before penalty triggers
Duration
Lifetime
Follows you even if you switch plans
The Official CMS Formula (42 CFR 423.286)
1% × $38.99 × Uncovered Months
Rounded to the nearest $0.10 and added permanently to your monthly Part D premium. The base premium is updated by CMS each year — your uncovered month count is fixed, but the dollar amount can change annually.
⚠ When does the penalty clock start?
You receive a 7-month Initial Enrollment Period (IEP): 3 months before your 65th birthday month, your birthday month, and 3 months after. The penalty clock starts the month after your IEP ends — not your birthday. The clock also never goes before June 2006, when Part D began.
You receive a 7-month Initial Enrollment Period (IEP): 3 months before your 65th birthday month, your birthday month, and 3 months after. The penalty clock starts the month after your IEP ends — not your birthday. The clock also never goes before June 2006, when Part D began.
ℹ The 63-Day Consecutive Gap Rule
Per 42 CFR 423.46, a penalty applies only if you go 63 or more consecutive days without creditable coverage after your IEP ends. If you lose coverage and re-enroll in Part D within 63 days, that gap is excused entirely and those months don't count.
Per 42 CFR 423.46, a penalty applies only if you go 63 or more consecutive days without creditable coverage after your IEP ends. If you lose coverage and re-enroll in Part D within 63 days, that gap is excused entirely and those months don't count.
✓ Penalty Exemptions (CMS)
• Extra Help / LIS — penalty fully waived
• Continuous creditable coverage — employer/union plans, VA, TRICARE, FEHB, PACE, State Pharmaceutical Assistance Programs, some Medigap policies
• Disability enrollees — penalty waived when you turn 65 and a new IEP begins
• Medicare Cost Plan enrollees with drug coverage
• Extra Help / LIS — penalty fully waived
• Continuous creditable coverage — employer/union plans, VA, TRICARE, FEHB, PACE, State Pharmaceutical Assistance Programs, some Medigap policies
• Disability enrollees — penalty waived when you turn 65 and a new IEP begins
• Medicare Cost Plan enrollees with drug coverage
All examples use the 2026 national base beneficiary premium of $38.99. Formula: round(1% × $38.99 × months, $0.10).
| Uncovered Months | Monthly Penalty | Annual Extra | Severity |
|---|---|---|---|
| 0 months | $0.00 | $0.00 | None |
| 7 months (CMS example) | $2.70 | $32.40 | Low |
| 14 months (CMS example) | $5.50 | $66.00 | Low |
| 24 months (2 yrs) | $9.40 | $112.80 | Low |
| 36 months (3 yrs) | $14.00 | $168.00 | Medium |
| 60 months (5 yrs) | $23.40 | $280.80 | Medium |
| 84 months (7 yrs) | $32.80 | $393.60 | High |
| 120 months (10 yrs) | $46.80 | $561.60 | Severe |
Official CMS Example (medicare.gov 2026): 14 uncovered months → 14% × $38.99 = $5.46, rounded to $5.50/month.
CMS adjusts the base premium annually. Your penalty percentage is fixed, but the dollar amount may change slightly each January.
When exactly does my penalty clock start?▶
The clock starts the month after your 7-month Initial Enrollment Period (IEP) ends. Your IEP = 3 months before your 65th birthday month + birthday month + 3 months after. Example: turn 65 in June → IEP = March–September → penalty clock starts October 1st. The clock also cannot go back before June 2006.
What is the 63-day grace period exactly?▶
Per 42 CFR 423.46, the LEP applies only when you have a continuous gap of 63 or more consecutive days without creditable coverage after your IEP. If you lose employer coverage and enroll in Part D within 63 days, that gap is fully excused. After day 64, every full calendar month without coverage counts toward your penalty.
Does the penalty dollar amount change each year?▶
Yes. CMS updates the national base beneficiary premium every January. In 2025 it was $36.78; in 2026 it is $38.99. Your number of uncovered months is permanently fixed, but because the formula multiplies by the current year's base premium, your actual monthly penalty amount may go up or down slightly each year.
Can the penalty ever be removed?▶
Rarely. The penalty is permanent in most cases. You can appeal to C2C Innovative Solutions (CMS's LEP appeals contractor) if you believe Medicare didn't account for creditable coverage you had, or if there was a calculation error. To appeal, complete the appeal form from your plan and submit documentation of your coverage history. Extra Help recipients and disability-to-65 enrollees are exempt.
Does the penalty follow me if I switch plans?▶
Yes. The LEP is attached to your Medicare record, not a specific plan. It follows you to any Part D plan — stand-alone PDP or Medicare Advantage with drug coverage (MA-PD).
What qualifies as creditable coverage?▶
Coverage that is actuarially equivalent to or better than Medicare's standard Part D benefit. This includes most employer/union drug plans, VA drug benefits, TRICARE, FEHB (federal employee plans), PACE, Indian Health Service, and qualifying State Pharmaceutical Assistance Programs. Plans are required to notify you annually in writing whether their coverage is creditable.
When can I enroll if I missed my window?▶
Annual Enrollment Period (AEP): October 15 – December 7 each year, coverage effective January 1. If you recently lost creditable employer coverage, you have a 63-day Special Enrollment Period (SEP). A licensed Medicare specialist can confirm your window and compare plans in your area.
Medicare Required Disclaimer: We are not connected with or endorsed by the United States government or the federal Medicare program. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE or your local SHIP office to get information on all of your options.