Two different Medicare penalties often get lumped together as one, but they are separate charges with separate math and separate triggers. Skipping Part D drug coverage, even for a matter of months, can mean paying its penalty for as long as a person keeps Medicare drug coverage, regardless of what happens with the Part B penalty most retirees have heard more about. A beneficiary who avoids one penalty entirely can still end up owing the other, because the circumstances that excuse each one do not always line up.
How the Part D Penalty Adds Up, Month by Month
According to Medicare’s page on avoiding late enrollment penalties, a person owes an extra 1% of the “national base beneficiary premium” for every month they go 63 days or more without Medicare drug coverage or other creditable drug coverage after their Initial Enrollment Period ends. That works out to roughly 12% a year for each full year of the gap. Medicare’s own worked example shows what that means in dollars: someone who waited 14 months to join a Medicare drug plan would owe a 14% penalty, calculated against the 2026 national base beneficiary premium of $38.99, for a monthly penalty of $5.50 added on top of whatever premium their chosen plan charges. Because the national base beneficiary premium changes every year, the dollar penalty can shift year to year even though the percentage stays fixed to the length of the original gap.
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Why It Is a Separate Charge From the Part B Penalty
The Part B penalty runs on entirely different math. Medicare adds an extra 10% to the standard Part B premium for each full 12-month period a person could have signed up for Part B but didn’t, unless a special enrollment period applies. Medicare’s example: someone who waited 24 months to sign up owes a 20% penalty on top of the 2026 standard Part B premium of $202.90, bringing the monthly total to $243.50. A retiree can end up owing both penalties at once, since the coverage that excuses a Part B penalty, typically active employer group coverage, is not automatically the same coverage that counts as creditable for Part D. Someone who had employer health insurance without a drug benefit attached, for example, could clear the Part B bar while still accumulating a Part D penalty in the background.
What Counts as Creditable Drug Coverage
The Part D penalty is generally avoided in only two ways: carrying creditable drug coverage, meaning coverage Medicare expects to pay, on average, at least as much as standard Part D, or qualifying for Extra Help, the program that assists with Medicare drug costs for people with limited income and resources. Coverage through a former employer or union retiree plan, TRICARE, or the VA can qualify as creditable, but a beneficiary is not supposed to assume it does; the employer or plan is required to send a notice each year stating whether the coverage meets that bar, and that notice is the proof a beneficiary needs if a Part D penalty is ever challenged later. A retiree who loses that creditable coverage involuntarily, for instance when a former employer drops retiree drug benefits altogether, generally gets a separate window to join a Medicare drug plan without being treated as having had a gap, provided the move happens promptly rather than months after the coverage ends.
Why the Penalty Follows the Person, Not the Plan
The Part D penalty attaches to the individual rather than to whichever specific plan they first joined. A beneficiary who switches from one stand-alone Medicare drug plan to another during an enrollment period does not shed the penalty in the move; the new plan simply inherits the obligation to add the same percentage to its own premium. The same is true for someone who moves into a Medicare Advantage plan that includes drug coverage, since that combined plan still counts as Medicare drug coverage for penalty purposes. The only way the penalty stops being charged is if the person stops carrying any Medicare drug coverage at all, at which point it would simply be reassessed, likely at a higher percentage, whenever they eventually re-enroll.
Escaping or Disputing a Penalty Already on the Books
Once someone joins a Medicare drug plan, the plan is responsible for telling them whether a penalty applies and what the premium, including that penalty, will be. Medicare’s guidance also allows a beneficiary who believes the penalty was calculated incorrectly, because the coverage gap didn’t actually happen as recorded, or because coverage held during the gap should have counted as creditable, to raise that disagreement rather than simply accept the bill. Because the penalty is recalculated using whatever the current national base beneficiary premium happens to be, it is also not a fixed dollar amount locked in at the time of the gap; it moves with the annual number even though the underlying percentage never changes.
Medicare’s own comparison of the two penalties makes the separation explicit: a retiree who successfully avoided a Part B penalty through a qualifying special enrollment period should not assume that protection extends automatically to Part D, since the drug-coverage clock runs on its own terms.
This article was produced with the assistance of AI and reviewed by The Financial Wire editorial team.
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Warren Cohen is a finance writer based in Phoenix, Arizona, covering personal finance topics including credit, banking, and beginner investing. He earned his degree in business administration from Arizona State University and began his career working in consumer finance, where he gained direct experience with lending and credit systems. He now writes for personal finance websites and fintech platforms, focusing on clear, practical content that helps readers make informed financial decisions.
