What is the Medicare Part D late enrollment penalty?
The Part D late enrollment penalty is 1% of the national base beneficiary premium — $38.99 in 2026 — for every full month you went without creditable drug coverage after your Initial Enrollment Period ended. It is added to your premium for as long as you have Part D.
- The 2026 national base beneficiary premium is $38.99 a month.
- The penalty is 1% of that figure per full uncovered month, rounded to the nearest 10 cents.
- It is permanent — not a one-time charge — and it is recalculated each year against the new base premium.
- People who qualify for Extra Help do not pay the penalty.
How the amount is worked out
Medicare counts the number of full months after your Initial Enrollment Period closed during which you had neither Part D nor other creditable drug coverage. Each of those months adds 1% of the national base beneficiary premium. At the 2026 figure of $38.99, a fourteen-month gap works out to 14% — about $5.50 a month — added on top of whatever your chosen plan charges.
Because the base premium is reset every year, the penalty is not frozen at the amount you first see. It moves with the base figure, which is why a gap that looks small at 65 keeps costing more over a long retirement.
What counts as creditable coverage
Creditable coverage means drug coverage expected to pay, on average, at least as much as standard Medicare drug coverage. Employer and union plans, VA benefits and TRICARE usually qualify, and months under that coverage do not count toward the penalty. Plans are required to tell you in writing each year whether their coverage is creditable — that notice is the document to keep.
What does not count: going without any drug plan because you take no prescriptions. The penalty applies regardless of whether you needed medication during the gap.
If you think the penalty is wrong
You can ask for a reconsideration if Medicare has the dates wrong or you had creditable coverage they do not know about. The form arrives with the letter announcing the penalty, and there is a deadline on it. Gather the creditable-coverage notices from the employer or plan before you file.
Sources
- Medicare.gov — Part D late enrollment penalty U.S. Centers for Medicare & Medicaid Services
- CMS 2026 Medicare Parts A & B premiums and deductibles Centers for Medicare & Medicaid Services
Run the numbers yourself
Part D penalty calculator
See what going without drug coverage adds to your Part D premium — for as long as you keep it.
Medicare date calculator
See your seven-month Initial Enrollment Period, your earliest coverage date, and your Medigap window.