American Insurance · PUBLISHED 15 JUL 2026 · VERIFIED 15 JUL 2026 · US EDITION

Your Guide to the Medicare Part D Penalty That Never Goes Away

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A 12-month delay without creditable drug coverage can permanently add about $4.70 per month to a Medicare Part D premium in 2026, because the penalty is 1% of the national base beneficiary premium, which CMS says is $38.99 for 2026.

The number that matters

The central number is 1% per uncovered month: Medicare’s Part D late enrollment penalty is calculated as 1% of the national base beneficiary premium for each full month without creditable drug coverage, and CMS says the 2024 base was $34.70 while Medicare.gov says you can also owe a higher premium depending on income.

How it quietly costs you

The first hidden cost is waiting more than 63 days without creditable drug coverage after first becoming Medicare-eligible, which triggers the Part D late enrollment penalty. The mechanism is simple: Medicare adds 1% of the national base beneficiary premium for each full uncovered month, and the charge is permanent as long as you have Part D coverage.

For 2026, that means each uncovered month adds about $0.39 to your monthly premium, because 1% of the 2026 base beneficiary premium of $38.99 is about $0.39. A 12-month delay therefore adds about $4.70 per month forever; a 24-month delay adds about $9.40 per month forever.

Old vs better: “No drug needs, so I can skip Part D” is the costly choice; joining on time with creditable coverage avoids the penalty entirely.

The second, compounding trap

The second compounding cost is paying the penalty for life, because CMS says the late enrollment penalty is added to the monthly premium for as long as the person has Medicare drug coverage, even if they switch plans. That turns a short lapse into a long-run drag: a person with a 24-month delay would pay about $112.80 a year in extra premiums every year they remain enrolled, based on the 2026 penalty amount of about $9.40 per month.

CMS also notes the penalty is rounded to the nearest $0.10, which means even small delays lock in a recurring charge that does not disappear after the first bill. Medicare.gov further says beneficiaries may also pay a higher premium depending on income, so the Part D bill can rise from more than one direction at once.

What this looks like in practice

Linda, 66, part-time bookkeeper, $42,000 income, $18,000 in a Medicare Advantage plan with drug coverage, 7 years from retirement planning simplicity, and no current standalone Part D issue because she is newly eligible and considering delaying enrollment.

She would discover:

• A 4-month uncovered gap would not be harmless: the penalty is about $1.60 per month in 2026, because 4 months × 1% × $38.99 ≈ $1.56, rounded by CMS rules to the nearest $0.10.
• A 12-month gap is far more expensive than people assume: it adds about $4.70 per month for life, not a one-time fee.
• Going 63 days or more without creditable drug coverage is the trigger, so a short “I’ll wait until I need meds” strategy can still create a permanent surcharge.

The full cost of doing nothing

For Linda, combining a 12-month delay with the lifelong nature of the penalty means roughly $565 over 10 years in extra premiums, or about $1,130 over 20 years, before any income-related premium increases are counted. That estimate uses CMS’s 2026 base beneficiary premium of $38.99, a 12-month uncovered period, and the rule that the penalty is paid every month for as long as she has Part D coverage.

What to do about it

• Check whether your current drug coverage is creditable using your plan’s notice or HR materials, and compare it against Medicare’s rule that only creditable coverage prevents the penalty.

• Open your plan or employer coverage documents and look for the word “creditable.”

• Confirm there was no gap of 63+ days.

• Save the notice for proof if Medicare later asks.

• Good looks like: uninterrupted creditable coverage with no gap long enough to trigger the penalty.

• Enroll in Part D during your Initial Enrollment Period if you do not already have creditable coverage, using the official Medicare enrollment path on Medicare.gov.

• Go to Medicare enrollment in your Medicare account or enrollment materials.

• Pick a plan before your creditable coverage ends.

• Keep the confirmation showing your effective date.

• Good looks like: no uncovered gap after Medicare eligibility begins.

• Compare whether your income will also push up your Part D cost by checking Medicare’s premium rules and your plan’s monthly premium before you choose coverage.

• Review whether your modified adjusted gross income could trigger higher premiums.

• Compare Part D plan premium plus any income-related amount.

• Choose the least expensive plan that still keeps you continuously covered.

• Good looks like: the lowest total monthly premium that still preserves uninterrupted creditable coverage.

A myth worth clearing up

Myth: “If I don’t take any prescriptions, I can safely skip Part D.” Fact: Medicare says going 63 or more days without creditable drug coverage can trigger a permanent penalty, even if you do not currently use medications.

Sources

• CMS
• Medicare.gov

Researched 2026-07-15.

Corrections & disclosure: an AI-assisted, human-reviewed guide. Every figure is dated and sourced above. Spot something out of date or wrong? Tell us and we’ll correct it — corrections are noted here and in the video description.