You are not required to enroll in a Part D prescription drug plan; however, you will not have coverage for most prescription drugs if you don’t. If you don’t enroll in a Part D plan when you first become Medicare eligible, you will also incur a late enrollment penalty if you enroll later. You will have to pay a late enrollment penalty for any period of 63 or more days in a row when you don’t have Medicare drug coverage or other creditable prescription drug coverage after your initial enrollment period. In most cases, you will have to pay the penalty for as long as you have Medicare drug coverage.

The amount of the late enrollment penalty is dependent on how long you did not have Part D or creditable prescription drug coverage. The penalty is calculated by multiplying 1% of the “national base beneficiary premium” ($33.06 in 2021) times the number of full, uncovered months you didn’t have Part D or other creditable coverage. The monthly premium is rounded to the nearest $.10 and added to your monthly Part D premium.