How Can I Compare Medicare Part D Plans Before 2027 Open Enrollment?

A low premium can look like the bargain. But the truth is that a plan can recover that apparent savings through a deductible, a changed tier, or higher pharmacy cost sharing. The work is not glamorous, but neither is discovering in January that last year's plan no longer fits the prescriptions you fill. Build the comparison around the medicines and pharmacies in front of you, not around the plan name you recognize.

How do I find out whether my medications are covered by a Part D plan in 2027?

Use Medicare Plan Compare to enter the prescriptions you take, select your ZIP code, and add the pharmacies you use, then review each plan's drug coverage and estimated costs. Medicare.gov says an account can save drug and pharmacy information and lets people use those saved details to compare plan costs; the tool uses ZIP code to show plans available in the area.

Here is how to make that screen useful rather than decorative. Bring the prescription names and the details shown on the prescription labels or pharmacy records, then enter them carefully. Medicare.gov says people without an account can answer questions that improve cost estimates, although those answers do not change which plans are shown. That distinction matters: cost estimates become more useful when the information is complete, but the local plan list is based on location.

1. Enter every prescription you expect to fill rather than only the most expensive-looking one.
2. Add the pharmacies you actually could use, including a mail-order option if that is realistic for regularly taken medicines.
3. Open the formulary for each promising plan and check the specific drug, its tier, and any listed restrictions.
4. Compare the estimated full-year cost and the plan details side by side before treating a low monthly premium as a winner.

Medicare advises reviewing a plan's formulary before enrolling because plans choose the specific drugs they offer, even though each formulary must include at least two drugs in the most commonly prescribed categories and classes. Medicare.gov also states that plans must include most drugs in six protected classes, including cancer, HIV/AIDS, antidepressant, antipsychotic, anticonvulsant, and transplant immunosuppressant drugs. That is meaningful protection, not a shortcut around checking the actual drug list.

Read the formulary entry, not only the word “covered.” A covered drug can still sit on a cost-sharing tier or have restrictions that shape what you pay and how the prescription is handled. If a plan's listing raises a question that public data does not answer, use the plan materials or free, personalized counseling through SHIP, which CMS identifies in its Choosing Medicare Drug Coverage fact sheet.

Should I keep my current Part D plan if its premium is low but my copays changed?

No single feature, including a low premium, establishes whether keeping the plan is the lower-cost choice; compare the whole year's estimated drug cost using your current prescriptions and pharmacy choices. Medicare.gov states that total Part D cost includes the monthly premium, annual deductible, pharmacy copayments, and coinsurance.

The cheap-premium trap is easy to understand. A premium is the predictable payment you see first, while copays, coinsurance, and deductible exposure appear only when prescriptions are filled. For 2027, no Part D plan may have a deductible above $700, according to Medicare.gov's Part D cost guidance. After the deductible, Medicare.gov says enrollees pay 25% coinsurance for covered generic and brand-name drugs until covered Part D out-of-pocket spending reaches $2,400 in 2027; after that threshold, catastrophic coverage provides no out-of-pocket cost for covered Part D drugs for the rest of the 2027 calendar year.

Use the monthly Explanation of Benefits as your reality check. Medicare.gov says it lists prescriptions filled, what the plan paid, what you and others paid, the coverage stage, and amounts counting toward out-of-pocket and total drug costs. It does not predict next year, but it gives a grounded record of what drove spending this year. For a refresher on the prior year's mechanics, see How Do the 2026 Medicare Part D Deductible, 25% Coinsurance, and $2,100 Cap Work?.

Then read the Annual Notice of Change before assuming continuity. CMS requires plans to send it by October 31 before the upcoming contract year, and says the notice identifies upcoming benefit changes, including cost-sharing and drug-tier structure changes. CMS also requires a comprehensive or abridged formulary with the notice, providing at least 60 days to review medication coverage and changed cost sharing. A low premium with materially changed copays is not a minor footnote. It is the comparison.

Why did my prescription move to a higher tier for 2027?

A prescription can move to a higher tier because a plan added a generic or biosimilar version, or because manufacturer price increases raised coinsurance, according to Medicare.gov. A higher tier generally costs more than a lower tier, so the practical response is to verify the formulary entry and its stated terms rather than assume the old cost will continue.

Medicare.gov's drug-plan guidance is clear: “Generally, a drug in a lower tier will cost you less than a drug in a higher tier.” That is why the tier is not administrative clutter. It is a cost signal that must be read alongside the plan's deductible, copay or coinsurance, and pharmacy network.

CMS rules also spell out what change notices are meant to provide. For negative formulary changes during a contract year, plans generally must give affected enrollees 60 days' prior written notice or provide a 60-day supply at the prior terms at refill with written notice. Required notices identify the affected drug, whether it is removed or moved in cost-sharing status, the reason, alternatives and expected cost sharing, and the process for a coverage determination or exception.

There is a formal route when coverage or tiering creates a problem: Medicare.gov says an enrollee or prescriber can request a formulary or tiering exception, with the prescriber providing a supporting medical statement. That process does not guarantee approval. It does give the reader a defined question to raise with the plan and prescriber instead of treating a tier change as unexplained or unavoidable.

Finish the review with a short record: the plan's annual estimated cost, the formulary status of each prescription, the pharmacy price path, and any questions prompted by the notice. That record turns Open Enrollment from a guess based on a familiar premium into a choice grounded in the factors Medicare says determine drug costs.