Think of Part D as drug insurance with federal guardrails. Each plan keeps a list of covered drugs, called a formulary, sorts them into price tiers and works with a network of pharmacies. Medicare requires each plan to cover drugs in key classes and to meet a minimum value, but plans can choose which specific drugs and which prices within those rules.

Part D does not cover drugs given in a doctor’s office or hospital outpatient setting, like many infusions. Those generally fall under Part B instead.

KFF reports that 56% of all Part D enrollees were in Medicare Advantage drug plans in 2026. Which path fits you depends on how you get your medical coverage, not only on your drugs.

We counted the 2027 standalone plan filings in CMS’s plan files. A filing is one plan in one of Medicare’s 34 PDP regions, so a company that offers the same plan in all regions shows up 34 times. Medicare Plan Finder counts can differ slightly from ours.

Our count of CMS 2027 plan filings (323 total, 15 companies). Plans offered in your ZIP code may be fewer.

Five national companies account for more than 90% of standalone filings. Regional Blue Cross Blue Shield companies make up most of the rest, and they usually sell only in their home states.

Two kinds of cost add up. The premium is the same every month whether you fill a prescription or not. Cost sharing is what you pay when you pick up a drug: first the deductible, then a copay or coinsurance until the $2,400 cap, then nothing. CMS says the lowest standalone premium is $5.30 in most states, and 88% of people without Extra Help can find a basic plan at $10.30 or less, but low-premium plans may have higher drug costs.

People with higher incomes also pay an IRMAA surcharge on top of the premium. The coverage stages are broken down on our Part D coverage phases 2027 page.

To show what Part D may cost in a full year, we ran three drug budgets through the standard 2027 design with the average standalone premium of about $36 a month. Real plans use tier copays and may charge less for generics, so treat these as ranges, not quotes.

Our calculation from CMS 2027 standard-benefit parameters ($700 deductible on every drug, 25% coinsurance, $2,400 cap). Many plans skip the deductible on generic tiers, which would lower the first row.

The payment plan does not lower what you owe, but it can turn a large January pharmacy bill into smaller monthly payments. Our Medicare Prescription Payment Plan 2027 guide shows the monthly math.

Many people who take one or two generics wonder whether Part D is worth it. The answer usually turns on the late enrollment penalty and on what could happen later. If you go 63 days or more without Part D or other creditable drug coverage after you first become eligible, a penalty is added to your premium for as long as you have Part D.

We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE (TTY 1-877-486-2048) to get information on all of your options.