Medicare Part D Plan Comparison Guide
Compare Part D drug plans on the things that change your cost. Free, with no email or personal information needed.
Part D plans are not standardized the way Medigap plans are, so the best plan depends on your drug list. Some things are the same in every plan for 2026: a deductible of no more than $615, then 25% coinsurance until you have spent $2,100 out of pocket, then $0 for covered drugs for the rest of the year. What differs, and what you need to compare, is the premium, the tier each of your drugs is on, and whether your pharmacy is in the plan's preferred network. For 2027 coverage, which you choose during open enrollment (October 15 to December 7), the maximum deductible is $700 and the out-of-pocket cap is $2,400.
No official score ranks one Part D plan above another. The result depends on which drugs you take and where you fill them. The table below shows what is the same in every plan and what you have to compare. After that, answer two questions for a checklist of what to look at before you use Medicare's Plan Finder to see prices for your ZIP code.
What's the Same in Every Plan vs. What You Must Compare
| Same in every 2026 Part D plan | Varies by plan (compare these yourself) |
|---|---|
| Maximum annual deductible: $615 | Monthly premium, commonly $0 to $100 or more |
| 25% coinsurance during the initial coverage phase | Which specific drugs are covered (the formulary) |
| $2,100 out-of-pocket cap, then $0 for the rest of the year | Which tier each of your drugs is placed on |
| Extra Help copay caps (if you qualify): $5.10 generic / $12.65 brand | Preferred vs. standard pharmacy pricing for the same drug |
| Medicare Prescription Payment Plan (M3P) available to spread costs monthly | Plan star rating (1–5, a measure of quality and service) |
| Annual Enrollment Period: October 15 – December 7 | Mail-order discount availability and terms |
The right-hand column is different for every person, so no chart, this one included, can tell you the cheapest plan for your drugs. Medicare's official Plan Finder can, because it checks your medications and ZIP code against each plan's formulary and prices.
What Should You Compare?
This tells you what to look at, not which plan to buy.
Have your zip code and full drug list (including dosage) ready before you start. Plan Finder needs both to show your costs.
Tiers. Most plans sort drugs into four or five tiers:
- Tier 1: preferred generics, the lowest cost
- Tier 2: other generics
- Tier 3: preferred brand-name drugs
- Tier 4 or 5: non-preferred brands and specialty drugs, often with coinsurance in place of a flat copay
The same drug can be on Tier 2 in one plan and Tier 4 in another. That is why the plan with the lowest premium is often not the cheapest for you.
Pharmacies. A plan may list a low copay at its "preferred" pharmacies and a higher one at pharmacies that are only "in network." Check the copay at the pharmacy you use.
Restrictions. A drug can be on the formulary and still need prior authorization, step therapy (trying another drug first) or a quantity limit. Plan Finder shows these next to each drug.
The cap. If you take several medications, especially brand-name ones, you may reach the $2,100 out-of-pocket cap before the end of the year. After that every plan charges $0 for covered drugs. For people who will reach the cap, the premium and how early in the year the costs fall matter most. The Medicare Prescription Payment Plan can spread those costs across the year.
For a step-by-step method with a worked example, see how to compare Part D plans for your own medications.
Frequently Asked Questions
What is the best Medicare Part D plan?
No single plan is best. It depends on which drugs you take and which pharmacy you use. A plan that is cheapest for one person can be among the most expensive for someone on different medications, because each plan sets its own formulary and tiers.
How much does Medicare Part D cost in 2026?
Premiums differ by plan and insurer. The standard structure for 2026 is a deductible of up to $615, then 25% coinsurance in the initial coverage phase, and a $2,100 cap on out-of-pocket spending. After the cap, covered drugs cost $0 for the rest of the year.
What is a drug formulary tier?
Each Part D plan sorts covered drugs into tiers, typically from Tier 1 (preferred generics, lowest cost) to Tier 4 or 5 (specialty drugs, highest cost). The same drug can be on a different tier in different plans, so two plans with similar premiums can cost you very different amounts.
Can I switch Medicare Part D plans every year?
Yes. During the Annual Enrollment Period, October 15 through December 7, you can switch, join or drop a Part D plan for any reason. Changes take effect January 1.
What if I can't afford my Medicare Part D plan?
Extra Help (the Low-Income Subsidy) can remove your deductible, pay your premium up to a benchmark amount, and cap copays at $5.10 for generics and $12.65 for brand-name drugs in 2026, for people who meet the income and asset limits.
Do I need Part D if I don't take many medications?
Generally yes, unless you have other creditable drug coverage. If you go 63 days or more without Part D or other creditable coverage after you are first eligible, a late enrollment penalty is added to your premium for as long as you have Part D.
This guide explains the national structure that every 2026 Part D plan shares and gives general priorities based on your answers. It does not show or estimate plan premiums, formularies or pharmacy prices, which differ by insurer and location. Use Medicare's Plan Finder for figures for specific plans.