Part D Late Enrollment Penalty
How much is the Part D penalty?
The cost of the late enrollment penalty depends on how long you went without Part D or creditable prescription drug coverage.
Medicare calculates the penalty by multiplying 1% of the "national base beneficiary premium" ($33.06 in 2021, $33.37 in 2022) times the number of full, uncovered months you didn't have Part D or creditable coverage. The monthly premium is rounded to the nearest $.10 and added to your monthly Part D premium.
The national base beneficiary premium may change each year, so your penalty amount may also change each year.