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How do I compare Medicare Part D plans?

A step by step way to compare Part D drug plans in about half an hour, sorting by what a full year costs instead of the monthly premium.

Updated September 3, 2026 · 3 min read · by Gerino Alejos

An older couple at a kitchen table read a folded paper beside several pill bottles and a weekly pill organizer. — Sorting by total annual cost instead of premium is the whole trick. It is the only ranking that reflects what leaves your bank account.

Key points

Sort the plan list by what a full year costs you, not by the premium, the monthly bill for the coverage.
Build your drug list first, with the exact dose, the amount in each fill, and how often you refill it.
Then check the top three plans for rules that could block the drugs you take.

Comparing Part D plans, the part of Medicare that pays for prescriptions, takes about half an hour. You write down your drugs, run them through Medicare's own tool, and sort by what a full year costs. Then you check the plans at the top for rules that could get in the way.

The mistake is starting with the premium, the monthly bill.

Step 1: build your drug list

Write down every prescription you take. For each one, put down the exact dose, how much you get in a fill, and how often you refill it. Note whether you take the brand or the generic.

Include anything you take only now and then. A medicine you fill twice a year still counts.

Step 2: run it through the Plan Finder

The Plan Finder is that tool. Anyone can use it, and it does the math for you.

Go to Medicare.gov and enter your ZIP code.
Enter every drug with its dose.
Add the pharmacy you usually use. Add a second one and a mail order option so you can compare.
Sort the results by total estimated yearly cost.

Sorting by the yearly total instead of the premium reorders the list completely. The yearly total is the number that matches what leaves your bank account.

Step 3: check the top three for restrictions

A low yearly total is not the end of the check. Look at the first few plans for rules on your drugs.

Prior authorization, which means the plan has to approve a drug before it will pay for it.
Step therapy, which means you have to try a lower cost drug first.
Quantity limits, a cap on how much the plan covers, set below what you are prescribed.
Whether your pharmacy is preferred or standard. A preferred pharmacy has agreed to lower prices with the plan.

A plan that saves you money but puts step therapy on a medicine you are stable on is not a saving.

Step 4: sanity check the plan itself

The star rating, Medicare's own score for a plan's service and quality.
Whether the company answers the phone when you call it.
Whether the plan holds steady year to year, or keeps changing its formulary, the list of drugs it covers.

Step 5: decide, then set a reminder for next October

Sign up during your enrollment window. Then put a note in your calendar for the first week of October next year to run this again.

Formularies and tiers, the price levels a plan sorts its drugs into, change every January. A plan that fits you this year often does not next year.

Mistakes to avoid

Choosing on the premium alone. This is the most common error and the most expensive one.
Assuming your plan still fits you because it fit you last year.
Not entering exact doses, which can put a drug on a different tier.
Skipping the pharmacy step. Preferred and standard pricing can be far apart.
Reading a step therapy flag as fine print and moving past it.

If you want an agent to run it with you

We run this comparison as a matter of course, at no cost to you, across the plans sold at your address. Bring your pill bottles or a list from your pharmacy.

Start with your drug list, then read how to check a formulary and what Part D costs. To run the comparison with us, call our McAllen office at (956) 687 3334, or enter your ZIP code in the form on this page.

Common follow-up questions

How often should I compare plans?

Every fall during Annual Enrollment, the window when you can change drug plans, even if you are happy. Formularies and tiers change every January.

Does using an agent cost more?

No. Part D premiums are filed with the federal Medicare agency, and they are the same whether you sign up on your own or through a licensed agent.

What if I take no medications at all?

Compare on premium and pick a low cost plan, so you avoid the late enrollment penalty for going without drug coverage. Check again each fall. See whether you need Part D.

Want this looked at properly?

We are an independent agency in McAllen serving Hidalgo, Cameron and Starr counties. There is no obligation to talk it through.

Call (956) 687 3334

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