How is the Part D late enrollment penalty calculated?

The penalty is 1% of the national base beneficiary premium ($38.99 in 2026) multiplied by the number of full months you went without Part D or other creditable drug coverage, rounded to the nearest $0.10. For example, 24 months without coverage adds $9.40 to your monthly Part D premium.

How long does the Part D penalty last?

Generally for life. The penalty is added to your Medicare drug plan premium for as long as you have Part D coverage — it does not expire, and switching plans does not remove it. It is recalculated against each year’s national base beneficiary premium, so the dollar amount can change annually.

What counts as creditable drug coverage?

Coverage that is expected to pay, on average, at least as much as Medicare’s standard Part D benefit. Common examples: employer or union group coverage, VA drug coverage, TRICARE, and the Indian Health Service. Your plan must send you a creditable-coverage notice each year — keep those letters, because they are your proof if Medicare ever questions a gap.

I take no medications. Do I still need Part D?

You are not required to enroll, but every month you go without creditable coverage after your Initial Enrollment Period adds to a permanent penalty if you enroll later. Many people who take no medications enroll in the lowest-premium Part D plan in their area just to stop the penalty clock and keep coverage in place for the unexpected.

Can the penalty be removed or appealed?

In limited cases. If you believe the months were counted wrong — for example, you actually had creditable coverage — you can ask for a reconsideration when your plan notifies you of the penalty (your plan sends a form with the notice, and C2C Innovative Solutions handles the review). People who qualify for Extra Help do not pay the Part D late enrollment penalty.

Does the penalty apply to Medicare Advantage plans with drug coverage?

Yes. If you enroll late in any Medicare drug coverage — a standalone Part D plan or a Medicare Advantage plan that includes drug coverage (MAPD) — the same penalty is added to that plan’s premium.

Medicare Part D Late Enrollment Penalty: How It's Calculated and How to Avoid It

If you go without Medicare drug coverage — or other creditable drug coverage — for too long after you're first eligible, Medicare adds a surcharge to your Part D premium. It's small per month, but it lasts for as long as you have drug coverage, and it grows with every month you wait.

The penalty: 1% of the national base beneficiary premium ($38.99 in 2026) for each full month without creditable drug coverage, rounded to the nearest $0.10.

Worked example: $38.99 × 1% × 24 months = $9.40/month, added permanently to your Part D premium. Want your own number? Use our free Part D penalty calculator →

What Triggers the Penalty

Medicare assesses the penalty if all of these are true:

Your Initial Enrollment Period (IEP) — the 7-month window around your 65th birthday — has ended
You went 63 or more continuous days without Part D or other creditable drug coverage
You later enrolled in Medicare drug coverage (a standalone Part D plan or a Medicare Advantage plan with drug coverage)

The 63-day rule means short gaps are safe: switching employers or moving between plans won't trigger the penalty as long as the gap stays under 63 days. What catches people is the long, quiet gap — retiring at 65, skipping drug coverage because they take no medications, then enrolling at 68 when a prescription appears.

How the Penalty Is Calculated

Count the number of full months you were eligible for Part D but had no creditable drug coverage
Multiply that number by 1% of the national base beneficiary premium ($38.99 in 2026)
Round to the nearest $0.10 — that's your monthly penalty, added on top of your plan's premium

Unlike the Part B penalty, which counts full 12-month periods, the Part D penalty counts every single month. Here's what different gaps cost at the 2026 base premium:

Gap Without Coverage	Penalty %	Extra Per Month	Extra Per Year
6 months	6%	$2.30	$27.60
1 year	12%	$4.70	$56.40
2 years	24%	$9.40	$112.80
3 years	36%	$14.00	$168.00
5 years	60%	$23.40	$280.80

Enter your own gap in the Part D penalty calculator to see your exact monthly amount — no sign-up required.

The Penalty Is Permanent

Once assessed, the penalty stays attached to your Medicare drug coverage for as long as you have it. It doesn't expire after a few years, and changing plans doesn't reset it. Because the penalty is a percentage of the current year's national base beneficiary premium, the dollar amount is recalculated each year.

The 6% Cap: Why the Penalty Can't Spike Overnight

The Inflation Reduction Act caps year-over-year growth of the national base beneficiary premium at 6% per year through 2029. The 2026 base premium of $38.99 reflects exactly that cap — without it, CMS calculated the premium would have been far higher. The cap limits how fast an existing penalty grows, but it doesn't shrink one: the only way to stop the damage is to stop adding penalty months.

What Counts as Creditable Coverage

Creditable drug coverage is coverage expected to pay at least as much as Medicare's standard Part D benefit. Common examples:

Employer or union group coverage — most, but not all; check your annual notice
VA drug coverage — creditable for Part D (unlike its treatment for Part B)
TRICARE and the Indian Health Service

Your plan must send you a creditable-coverage notice every year, typically in September. Keep them — they're your proof if Medicare later questions a gap. Full details: creditable coverage and Medicare →

How to Avoid the Penalty

Enroll during your IEP if you don't have creditable coverage — even the cheapest Part D plan in your area stops the penalty clock. See how the enrollment periods work →
Watch the 63-day clock whenever coverage ends — losing employer coverage gives you a 2-month Special Enrollment Period to join a Part D plan
Confirm your coverage is creditable every year, and save the notice
Don't rely on COBRA lasting — COBRA drug coverage is often creditable while it lasts, but when it ends, the 63-day clock starts. Read the COBRA penalty trap →