Medicare Part D Fact Sheet
What is Medicare Part D?
Part D helps cover prescription drugs. Plans are offered by private insurers approved by Medicare.
What Part D Covers
Generic and brand-name drugs
Drugs on the plan’s formulary (covered drug list)
Coverage through tiers (different costs for different drug types)
Costs (2026)
Monthly premium: Varies by plan and location
Deductible: Up to the Medicare-set annual maximum (varies by plan)
Copays and coinsurance: Vary by drug tier and pharmacy choice
Penalties
If you don’t sign up for Medicare Part D when you’re first eligible and you don’t have creditable prescription drug coverage, Medicare adds a late enrollment penalty.
The penalty equals 1% of the national base Part D premium for each full month you were eligible but not enrolled.
This amount is added to your monthly Part D premium and lasts for as long as you have Part D.
Kevin’s Story
Kevin delayed enrolling in Medicare Part D for 20 months after he first became eligible. Because of that delay, he has a 20% late enrollment penalty.
In 2026, the national base Part D premium is $36.78. Kevin’s penalty is 20% of $36.78, which equals about $7.36 extra per month. This amount is added to his Part D premium permanently for as long as he has Part D.